1 //===------- SemaTemplate.cpp - Semantic Analysis for C++ Templates -------===//
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //===----------------------------------------------------------------------===//
8 // This file implements semantic analysis for C++ templates.
9 //===----------------------------------------------------------------------===//
11 #include "TreeTransform.h"
12 #include "clang/AST/ASTConsumer.h"
13 #include "clang/AST/ASTContext.h"
14 #include "clang/AST/DeclFriend.h"
15 #include "clang/AST/DeclTemplate.h"
16 #include "clang/AST/Expr.h"
17 #include "clang/AST/ExprCXX.h"
18 #include "clang/AST/RecursiveASTVisitor.h"
19 #include "clang/AST/TypeVisitor.h"
20 #include "clang/Basic/Builtins.h"
21 #include "clang/Basic/LangOptions.h"
22 #include "clang/Basic/PartialDiagnostic.h"
23 #include "clang/Basic/Stack.h"
24 #include "clang/Basic/TargetInfo.h"
25 #include "clang/Sema/DeclSpec.h"
26 #include "clang/Sema/Lookup.h"
27 #include "clang/Sema/Overload.h"
28 #include "clang/Sema/ParsedTemplate.h"
29 #include "clang/Sema/Scope.h"
30 #include "clang/Sema/SemaInternal.h"
31 #include "clang/Sema/Template.h"
32 #include "clang/Sema/TemplateDeduction.h"
33 #include "llvm/ADT/SmallBitVector.h"
34 #include "llvm/ADT/SmallString.h"
35 #include "llvm/ADT/StringExtras.h"
38 using namespace clang;
41 // Exported for use by Parser.
43 clang::getTemplateParamsRange(TemplateParameterList const * const *Ps,
45 if (!N) return SourceRange();
46 return SourceRange(Ps[0]->getTemplateLoc(), Ps[N-1]->getRAngleLoc());
49 /// \brief Determine whether the declaration found is acceptable as the name
50 /// of a template and, if so, return that template declaration. Otherwise,
53 /// Note that this may return an UnresolvedUsingValueDecl if AllowDependent
54 /// is true. In all other cases it will return a TemplateDecl (or null).
55 NamedDecl *Sema::getAsTemplateNameDecl(NamedDecl *D,
56 bool AllowFunctionTemplates,
57 bool AllowDependent) {
58 D = D->getUnderlyingDecl();
60 if (isa<TemplateDecl>(D)) {
61 if (!AllowFunctionTemplates && isa<FunctionTemplateDecl>(D))
67 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D)) {
68 // C++ [temp.local]p1:
69 // Like normal (non-template) classes, class templates have an
70 // injected-class-name (Clause 9). The injected-class-name
71 // can be used with or without a template-argument-list. When
72 // it is used without a template-argument-list, it is
73 // equivalent to the injected-class-name followed by the
74 // template-parameters of the class template enclosed in
75 // <>. When it is used with a template-argument-list, it
76 // refers to the specified class template specialization,
77 // which could be the current specialization or another
79 if (Record->isInjectedClassName()) {
80 Record = cast<CXXRecordDecl>(Record->getDeclContext());
81 if (Record->getDescribedClassTemplate())
82 return Record->getDescribedClassTemplate();
84 if (ClassTemplateSpecializationDecl *Spec
85 = dyn_cast<ClassTemplateSpecializationDecl>(Record))
86 return Spec->getSpecializedTemplate();
92 // 'using Dependent::foo;' can resolve to a template name.
93 // 'using typename Dependent::foo;' cannot (not even if 'foo' is an
94 // injected-class-name).
95 if (AllowDependent && isa<UnresolvedUsingValueDecl>(D))
101 void Sema::FilterAcceptableTemplateNames(LookupResult &R,
102 bool AllowFunctionTemplates,
103 bool AllowDependent) {
104 LookupResult::Filter filter = R.makeFilter();
105 while (filter.hasNext()) {
106 NamedDecl *Orig = filter.next();
107 if (!getAsTemplateNameDecl(Orig, AllowFunctionTemplates, AllowDependent))
113 bool Sema::hasAnyAcceptableTemplateNames(LookupResult &R,
114 bool AllowFunctionTemplates,
116 bool AllowNonTemplateFunctions) {
117 for (LookupResult::iterator I = R.begin(), IEnd = R.end(); I != IEnd; ++I) {
118 if (getAsTemplateNameDecl(*I, AllowFunctionTemplates, AllowDependent))
120 if (AllowNonTemplateFunctions &&
121 isa<FunctionDecl>((*I)->getUnderlyingDecl()))
128 TemplateNameKind Sema::isTemplateName(Scope *S,
130 bool hasTemplateKeyword,
131 const UnqualifiedId &Name,
132 ParsedType ObjectTypePtr,
133 bool EnteringContext,
134 TemplateTy &TemplateResult,
135 bool &MemberOfUnknownSpecialization) {
136 assert(getLangOpts().CPlusPlus && "No template names in C!");
138 DeclarationName TName;
139 MemberOfUnknownSpecialization = false;
141 switch (Name.getKind()) {
142 case UnqualifiedIdKind::IK_Identifier:
143 TName = DeclarationName(Name.Identifier);
146 case UnqualifiedIdKind::IK_OperatorFunctionId:
147 TName = Context.DeclarationNames.getCXXOperatorName(
148 Name.OperatorFunctionId.Operator);
151 case UnqualifiedIdKind::IK_LiteralOperatorId:
152 TName = Context.DeclarationNames.getCXXLiteralOperatorName(Name.Identifier);
156 return TNK_Non_template;
159 QualType ObjectType = ObjectTypePtr.get();
161 AssumedTemplateKind AssumedTemplate;
162 LookupResult R(*this, TName, Name.getBeginLoc(), LookupOrdinaryName);
163 if (LookupTemplateName(R, S, SS, ObjectType, EnteringContext,
164 MemberOfUnknownSpecialization, SourceLocation(),
166 return TNK_Non_template;
168 if (AssumedTemplate != AssumedTemplateKind::None) {
169 TemplateResult = TemplateTy::make(Context.getAssumedTemplateName(TName));
170 // Let the parser know whether we found nothing or found functions; if we
171 // found nothing, we want to more carefully check whether this is actually
172 // a function template name versus some other kind of undeclared identifier.
173 return AssumedTemplate == AssumedTemplateKind::FoundNothing
174 ? TNK_Undeclared_template
175 : TNK_Function_template;
179 return TNK_Non_template;
181 NamedDecl *D = nullptr;
182 if (R.isAmbiguous()) {
183 // If we got an ambiguity involving a non-function template, treat this
184 // as a template name, and pick an arbitrary template for error recovery.
185 bool AnyFunctionTemplates = false;
186 for (NamedDecl *FoundD : R) {
187 if (NamedDecl *FoundTemplate = getAsTemplateNameDecl(FoundD)) {
188 if (isa<FunctionTemplateDecl>(FoundTemplate))
189 AnyFunctionTemplates = true;
197 // If we didn't find any templates at all, this isn't a template name.
198 // Leave the ambiguity for a later lookup to diagnose.
199 if (!D && !AnyFunctionTemplates) {
200 R.suppressDiagnostics();
201 return TNK_Non_template;
204 // If the only templates were function templates, filter out the rest.
205 // We'll diagnose the ambiguity later.
207 FilterAcceptableTemplateNames(R);
210 // At this point, we have either picked a single template name declaration D
211 // or we have a non-empty set of results R containing either one template name
212 // declaration or a set of function templates.
214 TemplateName Template;
215 TemplateNameKind TemplateKind;
217 unsigned ResultCount = R.end() - R.begin();
218 if (!D && ResultCount > 1) {
219 // We assume that we'll preserve the qualifier from a function
220 // template name in other ways.
221 Template = Context.getOverloadedTemplateName(R.begin(), R.end());
222 TemplateKind = TNK_Function_template;
224 // We'll do this lookup again later.
225 R.suppressDiagnostics();
228 D = getAsTemplateNameDecl(*R.begin());
229 assert(D && "unambiguous result is not a template name");
232 if (isa<UnresolvedUsingValueDecl>(D)) {
233 // We don't yet know whether this is a template-name or not.
234 MemberOfUnknownSpecialization = true;
235 return TNK_Non_template;
238 TemplateDecl *TD = cast<TemplateDecl>(D);
240 if (SS.isSet() && !SS.isInvalid()) {
241 NestedNameSpecifier *Qualifier = SS.getScopeRep();
242 Template = Context.getQualifiedTemplateName(Qualifier,
243 hasTemplateKeyword, TD);
245 Template = TemplateName(TD);
248 if (isa<FunctionTemplateDecl>(TD)) {
249 TemplateKind = TNK_Function_template;
251 // We'll do this lookup again later.
252 R.suppressDiagnostics();
254 assert(isa<ClassTemplateDecl>(TD) || isa<TemplateTemplateParmDecl>(TD) ||
255 isa<TypeAliasTemplateDecl>(TD) || isa<VarTemplateDecl>(TD) ||
256 isa<BuiltinTemplateDecl>(TD) || isa<ConceptDecl>(TD));
258 isa<VarTemplateDecl>(TD) ? TNK_Var_template :
259 isa<ConceptDecl>(TD) ? TNK_Concept_template :
264 TemplateResult = TemplateTy::make(Template);
268 bool Sema::isDeductionGuideName(Scope *S, const IdentifierInfo &Name,
269 SourceLocation NameLoc,
270 ParsedTemplateTy *Template) {
272 bool MemberOfUnknownSpecialization = false;
274 // We could use redeclaration lookup here, but we don't need to: the
275 // syntactic form of a deduction guide is enough to identify it even
276 // if we can't look up the template name at all.
277 LookupResult R(*this, DeclarationName(&Name), NameLoc, LookupOrdinaryName);
278 if (LookupTemplateName(R, S, SS, /*ObjectType*/ QualType(),
279 /*EnteringContext*/ false,
280 MemberOfUnknownSpecialization))
283 if (R.empty()) return false;
284 if (R.isAmbiguous()) {
285 // FIXME: Diagnose an ambiguity if we find at least one template.
286 R.suppressDiagnostics();
290 // We only treat template-names that name type templates as valid deduction
292 TemplateDecl *TD = R.getAsSingle<TemplateDecl>();
293 if (!TD || !getAsTypeTemplateDecl(TD))
297 *Template = TemplateTy::make(TemplateName(TD));
301 bool Sema::DiagnoseUnknownTemplateName(const IdentifierInfo &II,
302 SourceLocation IILoc,
304 const CXXScopeSpec *SS,
305 TemplateTy &SuggestedTemplate,
306 TemplateNameKind &SuggestedKind) {
307 // We can't recover unless there's a dependent scope specifier preceding the
309 // FIXME: Typo correction?
310 if (!SS || !SS->isSet() || !isDependentScopeSpecifier(*SS) ||
311 computeDeclContext(*SS))
314 // The code is missing a 'template' keyword prior to the dependent template
316 NestedNameSpecifier *Qualifier = (NestedNameSpecifier*)SS->getScopeRep();
317 Diag(IILoc, diag::err_template_kw_missing)
318 << Qualifier << II.getName()
319 << FixItHint::CreateInsertion(IILoc, "template ");
321 = TemplateTy::make(Context.getDependentTemplateName(Qualifier, &II));
322 SuggestedKind = TNK_Dependent_template_name;
326 bool Sema::LookupTemplateName(LookupResult &Found,
327 Scope *S, CXXScopeSpec &SS,
329 bool EnteringContext,
330 bool &MemberOfUnknownSpecialization,
331 SourceLocation TemplateKWLoc,
332 AssumedTemplateKind *ATK) {
334 *ATK = AssumedTemplateKind::None;
336 Found.setTemplateNameLookup(true);
338 // Determine where to perform name lookup
339 MemberOfUnknownSpecialization = false;
340 DeclContext *LookupCtx = nullptr;
341 bool IsDependent = false;
342 if (!ObjectType.isNull()) {
343 // This nested-name-specifier occurs in a member access expression, e.g.,
344 // x->B::f, and we are looking into the type of the object.
345 assert(!SS.isSet() && "ObjectType and scope specifier cannot coexist");
346 LookupCtx = computeDeclContext(ObjectType);
347 IsDependent = !LookupCtx && ObjectType->isDependentType();
348 assert((IsDependent || !ObjectType->isIncompleteType() ||
349 ObjectType->castAs<TagType>()->isBeingDefined()) &&
350 "Caller should have completed object type");
352 // Template names cannot appear inside an Objective-C class or object type
355 // FIXME: This is wrong. For example:
357 // template<typename T> using Vec = T __attribute__((ext_vector_type(4)));
359 // vi.Vec<int>::~Vec<int>();
361 // ... should be accepted but we will not treat 'Vec' as a template name
362 // here. The right thing to do would be to check if the name is a valid
363 // vector component name, and look up a template name if not. And similarly
364 // for lookups into Objective-C class and object types, where the same
365 // problem can arise.
366 if (ObjectType->isObjCObjectOrInterfaceType() ||
367 ObjectType->isVectorType()) {
371 } else if (SS.isSet()) {
372 // This nested-name-specifier occurs after another nested-name-specifier,
373 // so long into the context associated with the prior nested-name-specifier.
374 LookupCtx = computeDeclContext(SS, EnteringContext);
375 IsDependent = !LookupCtx;
377 // The declaration context must be complete.
378 if (LookupCtx && RequireCompleteDeclContext(SS, LookupCtx))
382 bool ObjectTypeSearchedInScope = false;
383 bool AllowFunctionTemplatesInLookup = true;
385 // Perform "qualified" name lookup into the declaration context we
386 // computed, which is either the type of the base of a member access
387 // expression or the declaration context associated with a prior
388 // nested-name-specifier.
389 LookupQualifiedName(Found, LookupCtx);
391 // FIXME: The C++ standard does not clearly specify what happens in the
392 // case where the object type is dependent, and implementations vary. In
393 // Clang, we treat a name after a . or -> as a template-name if lookup
394 // finds a non-dependent member or member of the current instantiation that
395 // is a type template, or finds no such members and lookup in the context
396 // of the postfix-expression finds a type template. In the latter case, the
397 // name is nonetheless dependent, and we may resolve it to a member of an
398 // unknown specialization when we come to instantiate the template.
399 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
402 if (!SS.isSet() && (ObjectType.isNull() || Found.empty())) {
403 // C++ [basic.lookup.classref]p1:
404 // In a class member access expression (5.2.5), if the . or -> token is
405 // immediately followed by an identifier followed by a <, the
406 // identifier must be looked up to determine whether the < is the
407 // beginning of a template argument list (14.2) or a less-than operator.
408 // The identifier is first looked up in the class of the object
409 // expression. If the identifier is not found, it is then looked up in
410 // the context of the entire postfix-expression and shall name a class
413 LookupName(Found, S);
415 if (!ObjectType.isNull()) {
416 // FIXME: We should filter out all non-type templates here, particularly
417 // variable templates and concepts. But the exclusion of alias templates
418 // and template template parameters is a wording defect.
419 AllowFunctionTemplatesInLookup = false;
420 ObjectTypeSearchedInScope = true;
423 IsDependent |= Found.wasNotFoundInCurrentInstantiation();
426 if (Found.isAmbiguous())
429 if (ATK && !SS.isSet() && ObjectType.isNull() && TemplateKWLoc.isInvalid()) {
430 // C++2a [temp.names]p2:
431 // A name is also considered to refer to a template if it is an
432 // unqualified-id followed by a < and name lookup finds either one or more
433 // functions or finds nothing.
435 // To keep our behavior consistent, we apply the "finds nothing" part in
436 // all language modes, and diagnose the empty lookup in ActOnCallExpr if we
437 // successfully form a call to an undeclared template-id.
439 getLangOpts().CPlusPlus2a &&
440 std::all_of(Found.begin(), Found.end(), [](NamedDecl *ND) {
441 return isa<FunctionDecl>(ND->getUnderlyingDecl());
443 if (AllFunctions || (Found.empty() && !IsDependent)) {
444 // If lookup found any functions, or if this is a name that can only be
445 // used for a function, then strongly assume this is a function
447 *ATK = (Found.empty() && Found.getLookupName().isIdentifier())
448 ? AssumedTemplateKind::FoundNothing
449 : AssumedTemplateKind::FoundFunctions;
455 if (Found.empty() && !IsDependent) {
456 // If we did not find any names, attempt to correct any typos.
457 DeclarationName Name = Found.getLookupName();
459 // Simple filter callback that, for keywords, only accepts the C++ *_cast
460 DefaultFilterCCC FilterCCC{};
461 FilterCCC.WantTypeSpecifiers = false;
462 FilterCCC.WantExpressionKeywords = false;
463 FilterCCC.WantRemainingKeywords = false;
464 FilterCCC.WantCXXNamedCasts = true;
465 if (TypoCorrection Corrected =
466 CorrectTypo(Found.getLookupNameInfo(), Found.getLookupKind(), S,
467 &SS, FilterCCC, CTK_ErrorRecovery, LookupCtx)) {
468 if (auto *ND = Corrected.getFoundDecl())
470 FilterAcceptableTemplateNames(Found);
471 if (Found.isAmbiguous()) {
473 } else if (!Found.empty()) {
474 Found.setLookupName(Corrected.getCorrection());
476 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
477 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
478 Name.getAsString() == CorrectedStr;
479 diagnoseTypo(Corrected, PDiag(diag::err_no_member_template_suggest)
480 << Name << LookupCtx << DroppedSpecifier
483 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest) << Name);
489 NamedDecl *ExampleLookupResult =
490 Found.empty() ? nullptr : Found.getRepresentativeDecl();
491 FilterAcceptableTemplateNames(Found, AllowFunctionTemplatesInLookup);
494 MemberOfUnknownSpecialization = true;
498 // If a 'template' keyword was used, a lookup that finds only non-template
499 // names is an error.
500 if (ExampleLookupResult && TemplateKWLoc.isValid()) {
501 Diag(Found.getNameLoc(), diag::err_template_kw_refers_to_non_template)
502 << Found.getLookupName() << SS.getRange();
503 Diag(ExampleLookupResult->getUnderlyingDecl()->getLocation(),
504 diag::note_template_kw_refers_to_non_template)
505 << Found.getLookupName();
512 if (S && !ObjectType.isNull() && !ObjectTypeSearchedInScope &&
513 !getLangOpts().CPlusPlus11) {
514 // C++03 [basic.lookup.classref]p1:
515 // [...] If the lookup in the class of the object expression finds a
516 // template, the name is also looked up in the context of the entire
517 // postfix-expression and [...]
519 // Note: C++11 does not perform this second lookup.
520 LookupResult FoundOuter(*this, Found.getLookupName(), Found.getNameLoc(),
522 FoundOuter.setTemplateNameLookup(true);
523 LookupName(FoundOuter, S);
524 // FIXME: We silently accept an ambiguous lookup here, in violation of
526 FilterAcceptableTemplateNames(FoundOuter, /*AllowFunctionTemplates=*/false);
528 NamedDecl *OuterTemplate;
529 if (FoundOuter.empty()) {
530 // - if the name is not found, the name found in the class of the
531 // object expression is used, otherwise
532 } else if (FoundOuter.isAmbiguous() || !FoundOuter.isSingleResult() ||
534 getAsTemplateNameDecl(FoundOuter.getFoundDecl()))) {
535 // - if the name is found in the context of the entire
536 // postfix-expression and does not name a class template, the name
537 // found in the class of the object expression is used, otherwise
539 } else if (!Found.isSuppressingDiagnostics()) {
540 // - if the name found is a class template, it must refer to the same
541 // entity as the one found in the class of the object expression,
542 // otherwise the program is ill-formed.
543 if (!Found.isSingleResult() ||
544 getAsTemplateNameDecl(Found.getFoundDecl())->getCanonicalDecl() !=
545 OuterTemplate->getCanonicalDecl()) {
546 Diag(Found.getNameLoc(),
547 diag::ext_nested_name_member_ref_lookup_ambiguous)
548 << Found.getLookupName()
550 Diag(Found.getRepresentativeDecl()->getLocation(),
551 diag::note_ambig_member_ref_object_type)
553 Diag(FoundOuter.getFoundDecl()->getLocation(),
554 diag::note_ambig_member_ref_scope);
556 // Recover by taking the template that we found in the object
557 // expression's type.
565 void Sema::diagnoseExprIntendedAsTemplateName(Scope *S, ExprResult TemplateName,
567 SourceLocation Greater) {
568 if (TemplateName.isInvalid())
571 DeclarationNameInfo NameInfo;
573 LookupNameKind LookupKind;
575 DeclContext *LookupCtx = nullptr;
576 NamedDecl *Found = nullptr;
577 bool MissingTemplateKeyword = false;
579 // Figure out what name we looked up.
580 if (auto *DRE = dyn_cast<DeclRefExpr>(TemplateName.get())) {
581 NameInfo = DRE->getNameInfo();
582 SS.Adopt(DRE->getQualifierLoc());
583 LookupKind = LookupOrdinaryName;
584 Found = DRE->getFoundDecl();
585 } else if (auto *ME = dyn_cast<MemberExpr>(TemplateName.get())) {
586 NameInfo = ME->getMemberNameInfo();
587 SS.Adopt(ME->getQualifierLoc());
588 LookupKind = LookupMemberName;
589 LookupCtx = ME->getBase()->getType()->getAsCXXRecordDecl();
590 Found = ME->getMemberDecl();
591 } else if (auto *DSDRE =
592 dyn_cast<DependentScopeDeclRefExpr>(TemplateName.get())) {
593 NameInfo = DSDRE->getNameInfo();
594 SS.Adopt(DSDRE->getQualifierLoc());
595 MissingTemplateKeyword = true;
596 } else if (auto *DSME =
597 dyn_cast<CXXDependentScopeMemberExpr>(TemplateName.get())) {
598 NameInfo = DSME->getMemberNameInfo();
599 SS.Adopt(DSME->getQualifierLoc());
600 MissingTemplateKeyword = true;
602 llvm_unreachable("unexpected kind of potential template name");
605 // If this is a dependent-scope lookup, diagnose that the 'template' keyword
607 if (MissingTemplateKeyword) {
608 Diag(NameInfo.getBeginLoc(), diag::err_template_kw_missing)
609 << "" << NameInfo.getName().getAsString() << SourceRange(Less, Greater);
613 // Try to correct the name by looking for templates and C++ named casts.
614 struct TemplateCandidateFilter : CorrectionCandidateCallback {
616 TemplateCandidateFilter(Sema &S) : S(S) {
617 WantTypeSpecifiers = false;
618 WantExpressionKeywords = false;
619 WantRemainingKeywords = false;
620 WantCXXNamedCasts = true;
622 bool ValidateCandidate(const TypoCorrection &Candidate) override {
623 if (auto *ND = Candidate.getCorrectionDecl())
624 return S.getAsTemplateNameDecl(ND);
625 return Candidate.isKeyword();
628 std::unique_ptr<CorrectionCandidateCallback> clone() override {
629 return std::make_unique<TemplateCandidateFilter>(*this);
633 DeclarationName Name = NameInfo.getName();
634 TemplateCandidateFilter CCC(*this);
635 if (TypoCorrection Corrected = CorrectTypo(NameInfo, LookupKind, S, &SS, CCC,
636 CTK_ErrorRecovery, LookupCtx)) {
637 auto *ND = Corrected.getFoundDecl();
639 ND = getAsTemplateNameDecl(ND);
640 if (ND || Corrected.isKeyword()) {
642 std::string CorrectedStr(Corrected.getAsString(getLangOpts()));
643 bool DroppedSpecifier = Corrected.WillReplaceSpecifier() &&
644 Name.getAsString() == CorrectedStr;
645 diagnoseTypo(Corrected,
646 PDiag(diag::err_non_template_in_member_template_id_suggest)
647 << Name << LookupCtx << DroppedSpecifier
648 << SS.getRange(), false);
650 diagnoseTypo(Corrected,
651 PDiag(diag::err_non_template_in_template_id_suggest)
655 Diag(Found->getLocation(),
656 diag::note_non_template_in_template_id_found);
661 Diag(NameInfo.getLoc(), diag::err_non_template_in_template_id)
662 << Name << SourceRange(Less, Greater);
664 Diag(Found->getLocation(), diag::note_non_template_in_template_id_found);
667 /// ActOnDependentIdExpression - Handle a dependent id-expression that
668 /// was just parsed. This is only possible with an explicit scope
669 /// specifier naming a dependent type.
671 Sema::ActOnDependentIdExpression(const CXXScopeSpec &SS,
672 SourceLocation TemplateKWLoc,
673 const DeclarationNameInfo &NameInfo,
674 bool isAddressOfOperand,
675 const TemplateArgumentListInfo *TemplateArgs) {
676 DeclContext *DC = getFunctionLevelDeclContext();
678 // C++11 [expr.prim.general]p12:
679 // An id-expression that denotes a non-static data member or non-static
680 // member function of a class can only be used:
682 // - if that id-expression denotes a non-static data member and it
683 // appears in an unevaluated operand.
685 // If this might be the case, form a DependentScopeDeclRefExpr instead of a
686 // CXXDependentScopeMemberExpr. The former can instantiate to either
687 // DeclRefExpr or MemberExpr depending on lookup results, while the latter is
688 // always a MemberExpr.
689 bool MightBeCxx11UnevalField =
690 getLangOpts().CPlusPlus11 && isUnevaluatedContext();
692 // Check if the nested name specifier is an enum type.
694 if (NestedNameSpecifier *NNS = SS.getScopeRep())
695 IsEnum = dyn_cast_or_null<EnumType>(NNS->getAsType());
697 if (!MightBeCxx11UnevalField && !isAddressOfOperand && !IsEnum &&
698 isa<CXXMethodDecl>(DC) && cast<CXXMethodDecl>(DC)->isInstance()) {
699 QualType ThisType = cast<CXXMethodDecl>(DC)->getThisType();
701 // Since the 'this' expression is synthesized, we don't need to
702 // perform the double-lookup check.
703 NamedDecl *FirstQualifierInScope = nullptr;
705 return CXXDependentScopeMemberExpr::Create(
706 Context, /*This*/ nullptr, ThisType, /*IsArrow*/ true,
707 /*Op*/ SourceLocation(), SS.getWithLocInContext(Context), TemplateKWLoc,
708 FirstQualifierInScope, NameInfo, TemplateArgs);
711 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
715 Sema::BuildDependentDeclRefExpr(const CXXScopeSpec &SS,
716 SourceLocation TemplateKWLoc,
717 const DeclarationNameInfo &NameInfo,
718 const TemplateArgumentListInfo *TemplateArgs) {
719 // DependentScopeDeclRefExpr::Create requires a valid QualifierLoc
720 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
724 return DependentScopeDeclRefExpr::Create(
725 Context, QualifierLoc, TemplateKWLoc, NameInfo, TemplateArgs);
729 /// Determine whether we would be unable to instantiate this template (because
730 /// it either has no definition, or is in the process of being instantiated).
731 bool Sema::DiagnoseUninstantiableTemplate(SourceLocation PointOfInstantiation,
732 NamedDecl *Instantiation,
733 bool InstantiatedFromMember,
734 const NamedDecl *Pattern,
735 const NamedDecl *PatternDef,
736 TemplateSpecializationKind TSK,
737 bool Complain /*= true*/) {
738 assert(isa<TagDecl>(Instantiation) || isa<FunctionDecl>(Instantiation) ||
739 isa<VarDecl>(Instantiation));
741 bool IsEntityBeingDefined = false;
742 if (const TagDecl *TD = dyn_cast_or_null<TagDecl>(PatternDef))
743 IsEntityBeingDefined = TD->isBeingDefined();
745 if (PatternDef && !IsEntityBeingDefined) {
746 NamedDecl *SuggestedDef = nullptr;
747 if (!hasVisibleDefinition(const_cast<NamedDecl*>(PatternDef), &SuggestedDef,
748 /*OnlyNeedComplete*/false)) {
749 // If we're allowed to diagnose this and recover, do so.
750 bool Recover = Complain && !isSFINAEContext();
752 diagnoseMissingImport(PointOfInstantiation, SuggestedDef,
753 Sema::MissingImportKind::Definition, Recover);
759 if (!Complain || (PatternDef && PatternDef->isInvalidDecl()))
762 llvm::Optional<unsigned> Note;
763 QualType InstantiationTy;
764 if (TagDecl *TD = dyn_cast<TagDecl>(Instantiation))
765 InstantiationTy = Context.getTypeDeclType(TD);
767 Diag(PointOfInstantiation,
768 diag::err_template_instantiate_within_definition)
769 << /*implicit|explicit*/(TSK != TSK_ImplicitInstantiation)
771 // Not much point in noting the template declaration here, since
772 // we're lexically inside it.
773 Instantiation->setInvalidDecl();
774 } else if (InstantiatedFromMember) {
775 if (isa<FunctionDecl>(Instantiation)) {
776 Diag(PointOfInstantiation,
777 diag::err_explicit_instantiation_undefined_member)
778 << /*member function*/ 1 << Instantiation->getDeclName()
779 << Instantiation->getDeclContext();
780 Note = diag::note_explicit_instantiation_here;
782 assert(isa<TagDecl>(Instantiation) && "Must be a TagDecl!");
783 Diag(PointOfInstantiation,
784 diag::err_implicit_instantiate_member_undefined)
786 Note = diag::note_member_declared_at;
789 if (isa<FunctionDecl>(Instantiation)) {
790 Diag(PointOfInstantiation,
791 diag::err_explicit_instantiation_undefined_func_template)
793 Note = diag::note_explicit_instantiation_here;
794 } else if (isa<TagDecl>(Instantiation)) {
795 Diag(PointOfInstantiation, diag::err_template_instantiate_undefined)
796 << (TSK != TSK_ImplicitInstantiation)
798 Note = diag::note_template_decl_here;
800 assert(isa<VarDecl>(Instantiation) && "Must be a VarDecl!");
801 if (isa<VarTemplateSpecializationDecl>(Instantiation)) {
802 Diag(PointOfInstantiation,
803 diag::err_explicit_instantiation_undefined_var_template)
805 Instantiation->setInvalidDecl();
807 Diag(PointOfInstantiation,
808 diag::err_explicit_instantiation_undefined_member)
809 << /*static data member*/ 2 << Instantiation->getDeclName()
810 << Instantiation->getDeclContext();
811 Note = diag::note_explicit_instantiation_here;
814 if (Note) // Diagnostics were emitted.
815 Diag(Pattern->getLocation(), Note.getValue());
817 // In general, Instantiation isn't marked invalid to get more than one
818 // error for multiple undefined instantiations. But the code that does
819 // explicit declaration -> explicit definition conversion can't handle
820 // invalid declarations, so mark as invalid in that case.
821 if (TSK == TSK_ExplicitInstantiationDeclaration)
822 Instantiation->setInvalidDecl();
826 /// DiagnoseTemplateParameterShadow - Produce a diagnostic complaining
827 /// that the template parameter 'PrevDecl' is being shadowed by a new
828 /// declaration at location Loc. Returns true to indicate that this is
829 /// an error, and false otherwise.
830 void Sema::DiagnoseTemplateParameterShadow(SourceLocation Loc, Decl *PrevDecl) {
831 assert(PrevDecl->isTemplateParameter() && "Not a template parameter");
833 // C++ [temp.local]p4:
834 // A template-parameter shall not be redeclared within its
835 // scope (including nested scopes).
837 // Make this a warning when MSVC compatibility is requested.
838 unsigned DiagId = getLangOpts().MSVCCompat ? diag::ext_template_param_shadow
839 : diag::err_template_param_shadow;
840 Diag(Loc, DiagId) << cast<NamedDecl>(PrevDecl)->getDeclName();
841 Diag(PrevDecl->getLocation(), diag::note_template_param_here);
844 /// AdjustDeclIfTemplate - If the given decl happens to be a template, reset
845 /// the parameter D to reference the templated declaration and return a pointer
846 /// to the template declaration. Otherwise, do nothing to D and return null.
847 TemplateDecl *Sema::AdjustDeclIfTemplate(Decl *&D) {
848 if (TemplateDecl *Temp = dyn_cast_or_null<TemplateDecl>(D)) {
849 D = Temp->getTemplatedDecl();
855 ParsedTemplateArgument ParsedTemplateArgument::getTemplatePackExpansion(
856 SourceLocation EllipsisLoc) const {
857 assert(Kind == Template &&
858 "Only template template arguments can be pack expansions here");
859 assert(getAsTemplate().get().containsUnexpandedParameterPack() &&
860 "Template template argument pack expansion without packs");
861 ParsedTemplateArgument Result(*this);
862 Result.EllipsisLoc = EllipsisLoc;
866 static TemplateArgumentLoc translateTemplateArgument(Sema &SemaRef,
867 const ParsedTemplateArgument &Arg) {
869 switch (Arg.getKind()) {
870 case ParsedTemplateArgument::Type: {
872 QualType T = SemaRef.GetTypeFromParser(Arg.getAsType(), &DI);
874 DI = SemaRef.Context.getTrivialTypeSourceInfo(T, Arg.getLocation());
875 return TemplateArgumentLoc(TemplateArgument(T), DI);
878 case ParsedTemplateArgument::NonType: {
879 Expr *E = static_cast<Expr *>(Arg.getAsExpr());
880 return TemplateArgumentLoc(TemplateArgument(E), E);
883 case ParsedTemplateArgument::Template: {
884 TemplateName Template = Arg.getAsTemplate().get();
885 TemplateArgument TArg;
886 if (Arg.getEllipsisLoc().isValid())
887 TArg = TemplateArgument(Template, Optional<unsigned int>());
890 return TemplateArgumentLoc(TArg,
891 Arg.getScopeSpec().getWithLocInContext(
894 Arg.getEllipsisLoc());
898 llvm_unreachable("Unhandled parsed template argument");
901 /// Translates template arguments as provided by the parser
902 /// into template arguments used by semantic analysis.
903 void Sema::translateTemplateArguments(const ASTTemplateArgsPtr &TemplateArgsIn,
904 TemplateArgumentListInfo &TemplateArgs) {
905 for (unsigned I = 0, Last = TemplateArgsIn.size(); I != Last; ++I)
906 TemplateArgs.addArgument(translateTemplateArgument(*this,
910 static void maybeDiagnoseTemplateParameterShadow(Sema &SemaRef, Scope *S,
912 IdentifierInfo *Name) {
913 NamedDecl *PrevDecl = SemaRef.LookupSingleName(
914 S, Name, Loc, Sema::LookupOrdinaryName, Sema::ForVisibleRedeclaration);
915 if (PrevDecl && PrevDecl->isTemplateParameter())
916 SemaRef.DiagnoseTemplateParameterShadow(Loc, PrevDecl);
919 /// Convert a parsed type into a parsed template argument. This is mostly
920 /// trivial, except that we may have parsed a C++17 deduced class template
921 /// specialization type, in which case we should form a template template
922 /// argument instead of a type template argument.
923 ParsedTemplateArgument Sema::ActOnTemplateTypeArgument(TypeResult ParsedType) {
924 TypeSourceInfo *TInfo;
925 QualType T = GetTypeFromParser(ParsedType.get(), &TInfo);
927 return ParsedTemplateArgument();
928 assert(TInfo && "template argument with no location");
930 // If we might have formed a deduced template specialization type, convert
931 // it to a template template argument.
932 if (getLangOpts().CPlusPlus17) {
933 TypeLoc TL = TInfo->getTypeLoc();
934 SourceLocation EllipsisLoc;
935 if (auto PET = TL.getAs<PackExpansionTypeLoc>()) {
936 EllipsisLoc = PET.getEllipsisLoc();
937 TL = PET.getPatternLoc();
941 if (auto ET = TL.getAs<ElaboratedTypeLoc>()) {
942 SS.Adopt(ET.getQualifierLoc());
943 TL = ET.getNamedTypeLoc();
946 if (auto DTST = TL.getAs<DeducedTemplateSpecializationTypeLoc>()) {
947 TemplateName Name = DTST.getTypePtr()->getTemplateName();
949 Name = Context.getQualifiedTemplateName(SS.getScopeRep(),
950 /*HasTemplateKeyword*/ false,
951 Name.getAsTemplateDecl());
952 ParsedTemplateArgument Result(SS, TemplateTy::make(Name),
953 DTST.getTemplateNameLoc());
954 if (EllipsisLoc.isValid())
955 Result = Result.getTemplatePackExpansion(EllipsisLoc);
960 // This is a normal type template argument. Note, if the type template
961 // argument is an injected-class-name for a template, it has a dual nature
962 // and can be used as either a type or a template. We handle that in
963 // convertTypeTemplateArgumentToTemplate.
964 return ParsedTemplateArgument(ParsedTemplateArgument::Type,
965 ParsedType.get().getAsOpaquePtr(),
966 TInfo->getTypeLoc().getBeginLoc());
969 /// ActOnTypeParameter - Called when a C++ template type parameter
970 /// (e.g., "typename T") has been parsed. Typename specifies whether
971 /// the keyword "typename" was used to declare the type parameter
972 /// (otherwise, "class" was used), and KeyLoc is the location of the
973 /// "class" or "typename" keyword. ParamName is the name of the
974 /// parameter (NULL indicates an unnamed template parameter) and
975 /// ParamNameLoc is the location of the parameter name (if any).
976 /// If the type parameter has a default argument, it will be added
977 /// later via ActOnTypeParameterDefault.
978 NamedDecl *Sema::ActOnTypeParameter(Scope *S, bool Typename,
979 SourceLocation EllipsisLoc,
980 SourceLocation KeyLoc,
981 IdentifierInfo *ParamName,
982 SourceLocation ParamNameLoc,
983 unsigned Depth, unsigned Position,
984 SourceLocation EqualLoc,
985 ParsedType DefaultArg) {
986 assert(S->isTemplateParamScope() &&
987 "Template type parameter not in template parameter scope!");
989 bool IsParameterPack = EllipsisLoc.isValid();
990 TemplateTypeParmDecl *Param = TemplateTypeParmDecl::Create(
991 Context, Context.getTranslationUnitDecl(), KeyLoc, ParamNameLoc, Depth,
992 Position, ParamName, Typename, IsParameterPack);
993 Param->setAccess(AS_public);
995 if (Param->isParameterPack())
996 if (auto *LSI = getEnclosingLambda())
997 LSI->LocalPacks.push_back(Param);
1000 maybeDiagnoseTemplateParameterShadow(*this, S, ParamNameLoc, ParamName);
1002 // Add the template parameter into the current scope.
1004 IdResolver.AddDecl(Param);
1007 // C++0x [temp.param]p9:
1008 // A default template-argument may be specified for any kind of
1009 // template-parameter that is not a template parameter pack.
1010 if (DefaultArg && IsParameterPack) {
1011 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1012 DefaultArg = nullptr;
1015 // Handle the default argument, if provided.
1017 TypeSourceInfo *DefaultTInfo;
1018 GetTypeFromParser(DefaultArg, &DefaultTInfo);
1020 assert(DefaultTInfo && "expected source information for type");
1022 // Check for unexpanded parameter packs.
1023 if (DiagnoseUnexpandedParameterPack(ParamNameLoc, DefaultTInfo,
1024 UPPC_DefaultArgument))
1027 // Check the template argument itself.
1028 if (CheckTemplateArgument(Param, DefaultTInfo)) {
1029 Param->setInvalidDecl();
1033 Param->setDefaultArgument(DefaultTInfo);
1039 /// Check that the type of a non-type template parameter is
1042 /// \returns the (possibly-promoted) parameter type if valid;
1043 /// otherwise, produces a diagnostic and returns a NULL type.
1044 QualType Sema::CheckNonTypeTemplateParameterType(TypeSourceInfo *&TSI,
1045 SourceLocation Loc) {
1046 if (TSI->getType()->isUndeducedType()) {
1047 // C++17 [temp.dep.expr]p3:
1048 // An id-expression is type-dependent if it contains
1049 // - an identifier associated by name lookup with a non-type
1050 // template-parameter declared with a type that contains a
1051 // placeholder type (7.1.7.4),
1052 TSI = SubstAutoTypeSourceInfo(TSI, Context.DependentTy);
1055 return CheckNonTypeTemplateParameterType(TSI->getType(), Loc);
1058 QualType Sema::CheckNonTypeTemplateParameterType(QualType T,
1059 SourceLocation Loc) {
1060 // We don't allow variably-modified types as the type of non-type template
1062 if (T->isVariablyModifiedType()) {
1063 Diag(Loc, diag::err_variably_modified_nontype_template_param)
1068 // C++ [temp.param]p4:
1070 // A non-type template-parameter shall have one of the following
1071 // (optionally cv-qualified) types:
1073 // -- integral or enumeration type,
1074 if (T->isIntegralOrEnumerationType() ||
1075 // -- pointer to object or pointer to function,
1076 T->isPointerType() ||
1077 // -- reference to object or reference to function,
1078 T->isReferenceType() ||
1079 // -- pointer to member,
1080 T->isMemberPointerType() ||
1081 // -- std::nullptr_t.
1082 T->isNullPtrType() ||
1083 // Allow use of auto in template parameter declarations.
1084 T->isUndeducedType()) {
1085 // C++ [temp.param]p5: The top-level cv-qualifiers on the template-parameter
1086 // are ignored when determining its type.
1087 return T.getUnqualifiedType();
1090 // C++ [temp.param]p8:
1092 // A non-type template-parameter of type "array of T" or
1093 // "function returning T" is adjusted to be of type "pointer to
1094 // T" or "pointer to function returning T", respectively.
1095 if (T->isArrayType() || T->isFunctionType())
1096 return Context.getDecayedType(T);
1098 // If T is a dependent type, we can't do the check now, so we
1099 // assume that it is well-formed. Note that stripping off the
1100 // qualifiers here is not really correct if T turns out to be
1101 // an array type, but we'll recompute the type everywhere it's
1102 // used during instantiation, so that should be OK. (Using the
1103 // qualified type is equally wrong.)
1104 if (T->isDependentType())
1105 return T.getUnqualifiedType();
1107 Diag(Loc, diag::err_template_nontype_parm_bad_type)
1113 NamedDecl *Sema::ActOnNonTypeTemplateParameter(Scope *S, Declarator &D,
1116 SourceLocation EqualLoc,
1118 TypeSourceInfo *TInfo = GetTypeForDeclarator(D, S);
1120 // Check that we have valid decl-specifiers specified.
1121 auto CheckValidDeclSpecifiers = [this, &D] {
1124 // template-parameter:
1126 // parameter-declaration
1128 // ... A storage class shall not be specified in a template-parameter
1131 // The typedef specifier [...] shall not be used in the decl-specifier-seq
1132 // of a parameter-declaration
1133 const DeclSpec &DS = D.getDeclSpec();
1134 auto EmitDiag = [this](SourceLocation Loc) {
1135 Diag(Loc, diag::err_invalid_decl_specifier_in_nontype_parm)
1136 << FixItHint::CreateRemoval(Loc);
1138 if (DS.getStorageClassSpec() != DeclSpec::SCS_unspecified)
1139 EmitDiag(DS.getStorageClassSpecLoc());
1141 if (DS.getThreadStorageClassSpec() != TSCS_unspecified)
1142 EmitDiag(DS.getThreadStorageClassSpecLoc());
1145 // The inline specifier can be applied only to the declaration or
1146 // definition of a variable or function.
1148 if (DS.isInlineSpecified())
1149 EmitDiag(DS.getInlineSpecLoc());
1151 // [dcl.constexpr]p1:
1152 // The constexpr specifier shall be applied only to the definition of a
1153 // variable or variable template or the declaration of a function or
1154 // function template.
1156 if (DS.hasConstexprSpecifier())
1157 EmitDiag(DS.getConstexprSpecLoc());
1159 // [dcl.fct.spec]p1:
1160 // Function-specifiers can be used only in function declarations.
1162 if (DS.isVirtualSpecified())
1163 EmitDiag(DS.getVirtualSpecLoc());
1165 if (DS.hasExplicitSpecifier())
1166 EmitDiag(DS.getExplicitSpecLoc());
1168 if (DS.isNoreturnSpecified())
1169 EmitDiag(DS.getNoreturnSpecLoc());
1172 CheckValidDeclSpecifiers();
1174 if (TInfo->getType()->isUndeducedType()) {
1175 Diag(D.getIdentifierLoc(),
1176 diag::warn_cxx14_compat_template_nontype_parm_auto_type)
1177 << QualType(TInfo->getType()->getContainedAutoType(), 0);
1180 assert(S->isTemplateParamScope() &&
1181 "Non-type template parameter not in template parameter scope!");
1182 bool Invalid = false;
1184 QualType T = CheckNonTypeTemplateParameterType(TInfo, D.getIdentifierLoc());
1186 T = Context.IntTy; // Recover with an 'int' type.
1190 CheckFunctionOrTemplateParamDeclarator(S, D);
1192 IdentifierInfo *ParamName = D.getIdentifier();
1193 bool IsParameterPack = D.hasEllipsis();
1194 NonTypeTemplateParmDecl *Param = NonTypeTemplateParmDecl::Create(
1195 Context, Context.getTranslationUnitDecl(), D.getBeginLoc(),
1196 D.getIdentifierLoc(), Depth, Position, ParamName, T, IsParameterPack,
1198 Param->setAccess(AS_public);
1201 Param->setInvalidDecl();
1203 if (Param->isParameterPack())
1204 if (auto *LSI = getEnclosingLambda())
1205 LSI->LocalPacks.push_back(Param);
1208 maybeDiagnoseTemplateParameterShadow(*this, S, D.getIdentifierLoc(),
1211 // Add the template parameter into the current scope.
1213 IdResolver.AddDecl(Param);
1216 // C++0x [temp.param]p9:
1217 // A default template-argument may be specified for any kind of
1218 // template-parameter that is not a template parameter pack.
1219 if (Default && IsParameterPack) {
1220 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1224 // Check the well-formedness of the default template argument, if provided.
1226 // Check for unexpanded parameter packs.
1227 if (DiagnoseUnexpandedParameterPack(Default, UPPC_DefaultArgument))
1230 TemplateArgument Converted;
1231 ExprResult DefaultRes =
1232 CheckTemplateArgument(Param, Param->getType(), Default, Converted);
1233 if (DefaultRes.isInvalid()) {
1234 Param->setInvalidDecl();
1237 Default = DefaultRes.get();
1239 Param->setDefaultArgument(Default);
1245 /// ActOnTemplateTemplateParameter - Called when a C++ template template
1246 /// parameter (e.g. T in template <template \<typename> class T> class array)
1247 /// has been parsed. S is the current scope.
1248 NamedDecl *Sema::ActOnTemplateTemplateParameter(Scope* S,
1249 SourceLocation TmpLoc,
1250 TemplateParameterList *Params,
1251 SourceLocation EllipsisLoc,
1252 IdentifierInfo *Name,
1253 SourceLocation NameLoc,
1256 SourceLocation EqualLoc,
1257 ParsedTemplateArgument Default) {
1258 assert(S->isTemplateParamScope() &&
1259 "Template template parameter not in template parameter scope!");
1261 // Construct the parameter object.
1262 bool IsParameterPack = EllipsisLoc.isValid();
1263 TemplateTemplateParmDecl *Param =
1264 TemplateTemplateParmDecl::Create(Context, Context.getTranslationUnitDecl(),
1265 NameLoc.isInvalid()? TmpLoc : NameLoc,
1266 Depth, Position, IsParameterPack,
1268 Param->setAccess(AS_public);
1270 if (Param->isParameterPack())
1271 if (auto *LSI = getEnclosingLambda())
1272 LSI->LocalPacks.push_back(Param);
1274 // If the template template parameter has a name, then link the identifier
1275 // into the scope and lookup mechanisms.
1277 maybeDiagnoseTemplateParameterShadow(*this, S, NameLoc, Name);
1280 IdResolver.AddDecl(Param);
1283 if (Params->size() == 0) {
1284 Diag(Param->getLocation(), diag::err_template_template_parm_no_parms)
1285 << SourceRange(Params->getLAngleLoc(), Params->getRAngleLoc());
1286 Param->setInvalidDecl();
1289 // C++0x [temp.param]p9:
1290 // A default template-argument may be specified for any kind of
1291 // template-parameter that is not a template parameter pack.
1292 if (IsParameterPack && !Default.isInvalid()) {
1293 Diag(EqualLoc, diag::err_template_param_pack_default_arg);
1294 Default = ParsedTemplateArgument();
1297 if (!Default.isInvalid()) {
1298 // Check only that we have a template template argument. We don't want to
1299 // try to check well-formedness now, because our template template parameter
1300 // might have dependent types in its template parameters, which we wouldn't
1301 // be able to match now.
1303 // If none of the template template parameter's template arguments mention
1304 // other template parameters, we could actually perform more checking here.
1305 // However, it isn't worth doing.
1306 TemplateArgumentLoc DefaultArg = translateTemplateArgument(*this, Default);
1307 if (DefaultArg.getArgument().getAsTemplate().isNull()) {
1308 Diag(DefaultArg.getLocation(), diag::err_template_arg_not_valid_template)
1309 << DefaultArg.getSourceRange();
1313 // Check for unexpanded parameter packs.
1314 if (DiagnoseUnexpandedParameterPack(DefaultArg.getLocation(),
1315 DefaultArg.getArgument().getAsTemplate(),
1316 UPPC_DefaultArgument))
1319 Param->setDefaultArgument(Context, DefaultArg);
1325 /// ActOnTemplateParameterList - Builds a TemplateParameterList, optionally
1326 /// constrained by RequiresClause, that contains the template parameters in
1328 TemplateParameterList *
1329 Sema::ActOnTemplateParameterList(unsigned Depth,
1330 SourceLocation ExportLoc,
1331 SourceLocation TemplateLoc,
1332 SourceLocation LAngleLoc,
1333 ArrayRef<NamedDecl *> Params,
1334 SourceLocation RAngleLoc,
1335 Expr *RequiresClause) {
1336 if (ExportLoc.isValid())
1337 Diag(ExportLoc, diag::warn_template_export_unsupported);
1339 return TemplateParameterList::Create(
1340 Context, TemplateLoc, LAngleLoc,
1341 llvm::makeArrayRef(Params.data(), Params.size()),
1342 RAngleLoc, RequiresClause);
1345 static void SetNestedNameSpecifier(Sema &S, TagDecl *T,
1346 const CXXScopeSpec &SS) {
1348 T->setQualifierInfo(SS.getWithLocInContext(S.Context));
1351 DeclResult Sema::CheckClassTemplate(
1352 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
1353 CXXScopeSpec &SS, IdentifierInfo *Name, SourceLocation NameLoc,
1354 const ParsedAttributesView &Attr, TemplateParameterList *TemplateParams,
1355 AccessSpecifier AS, SourceLocation ModulePrivateLoc,
1356 SourceLocation FriendLoc, unsigned NumOuterTemplateParamLists,
1357 TemplateParameterList **OuterTemplateParamLists, SkipBodyInfo *SkipBody) {
1358 assert(TemplateParams && TemplateParams->size() > 0 &&
1359 "No template parameters");
1360 assert(TUK != TUK_Reference && "Can only declare or define class templates");
1361 bool Invalid = false;
1363 // Check that we can declare a template here.
1364 if (CheckTemplateDeclScope(S, TemplateParams))
1367 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
1368 assert(Kind != TTK_Enum && "can't build template of enumerated type");
1370 // There is no such thing as an unnamed class template.
1372 Diag(KWLoc, diag::err_template_unnamed_class);
1376 // Find any previous declaration with this name. For a friend with no
1377 // scope explicitly specified, we only look for tag declarations (per
1378 // C++11 [basic.lookup.elab]p2).
1379 DeclContext *SemanticContext;
1380 LookupResult Previous(*this, Name, NameLoc,
1381 (SS.isEmpty() && TUK == TUK_Friend)
1382 ? LookupTagName : LookupOrdinaryName,
1383 forRedeclarationInCurContext());
1384 if (SS.isNotEmpty() && !SS.isInvalid()) {
1385 SemanticContext = computeDeclContext(SS, true);
1386 if (!SemanticContext) {
1387 // FIXME: Horrible, horrible hack! We can't currently represent this
1388 // in the AST, and historically we have just ignored such friend
1389 // class templates, so don't complain here.
1390 Diag(NameLoc, TUK == TUK_Friend
1391 ? diag::warn_template_qualified_friend_ignored
1392 : diag::err_template_qualified_declarator_no_match)
1393 << SS.getScopeRep() << SS.getRange();
1394 return TUK != TUK_Friend;
1397 if (RequireCompleteDeclContext(SS, SemanticContext))
1400 // If we're adding a template to a dependent context, we may need to
1401 // rebuilding some of the types used within the template parameter list,
1402 // now that we know what the current instantiation is.
1403 if (SemanticContext->isDependentContext()) {
1404 ContextRAII SavedContext(*this, SemanticContext);
1405 if (RebuildTemplateParamsInCurrentInstantiation(TemplateParams))
1407 } else if (TUK != TUK_Friend && TUK != TUK_Reference)
1408 diagnoseQualifiedDeclaration(SS, SemanticContext, Name, NameLoc, false);
1410 LookupQualifiedName(Previous, SemanticContext);
1412 SemanticContext = CurContext;
1414 // C++14 [class.mem]p14:
1415 // If T is the name of a class, then each of the following shall have a
1416 // name different from T:
1417 // -- every member template of class T
1418 if (TUK != TUK_Friend &&
1419 DiagnoseClassNameShadow(SemanticContext,
1420 DeclarationNameInfo(Name, NameLoc)))
1423 LookupName(Previous, S);
1426 if (Previous.isAmbiguous())
1429 NamedDecl *PrevDecl = nullptr;
1430 if (Previous.begin() != Previous.end())
1431 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1433 if (PrevDecl && PrevDecl->isTemplateParameter()) {
1434 // Maybe we will complain about the shadowed template parameter.
1435 DiagnoseTemplateParameterShadow(NameLoc, PrevDecl);
1436 // Just pretend that we didn't see the previous declaration.
1440 // If there is a previous declaration with the same name, check
1441 // whether this is a valid redeclaration.
1442 ClassTemplateDecl *PrevClassTemplate =
1443 dyn_cast_or_null<ClassTemplateDecl>(PrevDecl);
1445 // We may have found the injected-class-name of a class template,
1446 // class template partial specialization, or class template specialization.
1447 // In these cases, grab the template that is being defined or specialized.
1448 if (!PrevClassTemplate && PrevDecl && isa<CXXRecordDecl>(PrevDecl) &&
1449 cast<CXXRecordDecl>(PrevDecl)->isInjectedClassName()) {
1450 PrevDecl = cast<CXXRecordDecl>(PrevDecl->getDeclContext());
1452 = cast<CXXRecordDecl>(PrevDecl)->getDescribedClassTemplate();
1453 if (!PrevClassTemplate && isa<ClassTemplateSpecializationDecl>(PrevDecl)) {
1455 = cast<ClassTemplateSpecializationDecl>(PrevDecl)
1456 ->getSpecializedTemplate();
1460 if (TUK == TUK_Friend) {
1461 // C++ [namespace.memdef]p3:
1462 // [...] When looking for a prior declaration of a class or a function
1463 // declared as a friend, and when the name of the friend class or
1464 // function is neither a qualified name nor a template-id, scopes outside
1465 // the innermost enclosing namespace scope are not considered.
1467 DeclContext *OutermostContext = CurContext;
1468 while (!OutermostContext->isFileContext())
1469 OutermostContext = OutermostContext->getLookupParent();
1472 (OutermostContext->Equals(PrevDecl->getDeclContext()) ||
1473 OutermostContext->Encloses(PrevDecl->getDeclContext()))) {
1474 SemanticContext = PrevDecl->getDeclContext();
1476 // Declarations in outer scopes don't matter. However, the outermost
1477 // context we computed is the semantic context for our new
1479 PrevDecl = PrevClassTemplate = nullptr;
1480 SemanticContext = OutermostContext;
1482 // Check that the chosen semantic context doesn't already contain a
1483 // declaration of this name as a non-tag type.
1484 Previous.clear(LookupOrdinaryName);
1485 DeclContext *LookupContext = SemanticContext;
1486 while (LookupContext->isTransparentContext())
1487 LookupContext = LookupContext->getLookupParent();
1488 LookupQualifiedName(Previous, LookupContext);
1490 if (Previous.isAmbiguous())
1493 if (Previous.begin() != Previous.end())
1494 PrevDecl = (*Previous.begin())->getUnderlyingDecl();
1497 } else if (PrevDecl &&
1498 !isDeclInScope(Previous.getRepresentativeDecl(), SemanticContext,
1500 PrevDecl = PrevClassTemplate = nullptr;
1502 if (auto *Shadow = dyn_cast_or_null<UsingShadowDecl>(
1503 PrevDecl ? Previous.getRepresentativeDecl() : nullptr)) {
1505 !(PrevClassTemplate &&
1506 PrevClassTemplate->getDeclContext()->getRedeclContext()->Equals(
1507 SemanticContext->getRedeclContext()))) {
1508 Diag(KWLoc, diag::err_using_decl_conflict_reverse);
1509 Diag(Shadow->getTargetDecl()->getLocation(),
1510 diag::note_using_decl_target);
1511 Diag(Shadow->getUsingDecl()->getLocation(), diag::note_using_decl) << 0;
1512 // Recover by ignoring the old declaration.
1513 PrevDecl = PrevClassTemplate = nullptr;
1517 if (PrevClassTemplate) {
1518 // Ensure that the template parameter lists are compatible. Skip this check
1519 // for a friend in a dependent context: the template parameter list itself
1520 // could be dependent.
1521 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1522 !TemplateParameterListsAreEqual(TemplateParams,
1523 PrevClassTemplate->getTemplateParameters(),
1528 // C++ [temp.class]p4:
1529 // In a redeclaration, partial specialization, explicit
1530 // specialization or explicit instantiation of a class template,
1531 // the class-key shall agree in kind with the original class
1532 // template declaration (7.1.5.3).
1533 RecordDecl *PrevRecordDecl = PrevClassTemplate->getTemplatedDecl();
1534 if (!isAcceptableTagRedeclaration(PrevRecordDecl, Kind,
1535 TUK == TUK_Definition, KWLoc, Name)) {
1536 Diag(KWLoc, diag::err_use_with_wrong_tag)
1538 << FixItHint::CreateReplacement(KWLoc, PrevRecordDecl->getKindName());
1539 Diag(PrevRecordDecl->getLocation(), diag::note_previous_use);
1540 Kind = PrevRecordDecl->getTagKind();
1543 // Check for redefinition of this class template.
1544 if (TUK == TUK_Definition) {
1545 if (TagDecl *Def = PrevRecordDecl->getDefinition()) {
1546 // If we have a prior definition that is not visible, treat this as
1547 // simply making that previous definition visible.
1548 NamedDecl *Hidden = nullptr;
1549 if (SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
1550 SkipBody->ShouldSkip = true;
1551 SkipBody->Previous = Def;
1552 auto *Tmpl = cast<CXXRecordDecl>(Hidden)->getDescribedClassTemplate();
1553 assert(Tmpl && "original definition of a class template is not a "
1555 makeMergedDefinitionVisible(Hidden);
1556 makeMergedDefinitionVisible(Tmpl);
1558 Diag(NameLoc, diag::err_redefinition) << Name;
1559 Diag(Def->getLocation(), diag::note_previous_definition);
1560 // FIXME: Would it make sense to try to "forget" the previous
1561 // definition, as part of error recovery?
1566 } else if (PrevDecl) {
1568 // A class template shall not have the same name as any other
1569 // template, class, function, object, enumeration, enumerator,
1570 // namespace, or type in the same scope (3.3), except as specified
1572 Diag(NameLoc, diag::err_redefinition_different_kind) << Name;
1573 Diag(PrevDecl->getLocation(), diag::note_previous_definition);
1577 // Check the template parameter list of this declaration, possibly
1578 // merging in the template parameter list from the previous class
1579 // template declaration. Skip this check for a friend in a dependent
1580 // context, because the template parameter list might be dependent.
1581 if (!(TUK == TUK_Friend && CurContext->isDependentContext()) &&
1582 CheckTemplateParameterList(
1585 ? PrevClassTemplate->getMostRecentDecl()->getTemplateParameters()
1587 (SS.isSet() && SemanticContext && SemanticContext->isRecord() &&
1588 SemanticContext->isDependentContext())
1589 ? TPC_ClassTemplateMember
1590 : TUK == TUK_Friend ? TPC_FriendClassTemplate : TPC_ClassTemplate,
1595 // If the name of the template was qualified, we must be defining the
1596 // template out-of-line.
1597 if (!SS.isInvalid() && !Invalid && !PrevClassTemplate) {
1598 Diag(NameLoc, TUK == TUK_Friend ? diag::err_friend_decl_does_not_match
1599 : diag::err_member_decl_does_not_match)
1600 << Name << SemanticContext << /*IsDefinition*/true << SS.getRange();
1605 // If this is a templated friend in a dependent context we should not put it
1606 // on the redecl chain. In some cases, the templated friend can be the most
1607 // recent declaration tricking the template instantiator to make substitutions
1609 // FIXME: Figure out how to combine with shouldLinkDependentDeclWithPrevious
1610 bool ShouldAddRedecl
1611 = !(TUK == TUK_Friend && CurContext->isDependentContext());
1613 CXXRecordDecl *NewClass =
1614 CXXRecordDecl::Create(Context, Kind, SemanticContext, KWLoc, NameLoc, Name,
1615 PrevClassTemplate && ShouldAddRedecl ?
1616 PrevClassTemplate->getTemplatedDecl() : nullptr,
1617 /*DelayTypeCreation=*/true);
1618 SetNestedNameSpecifier(*this, NewClass, SS);
1619 if (NumOuterTemplateParamLists > 0)
1620 NewClass->setTemplateParameterListsInfo(
1621 Context, llvm::makeArrayRef(OuterTemplateParamLists,
1622 NumOuterTemplateParamLists));
1624 // Add alignment attributes if necessary; these attributes are checked when
1625 // the ASTContext lays out the structure.
1626 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
1627 AddAlignmentAttributesForRecord(NewClass);
1628 AddMsStructLayoutForRecord(NewClass);
1631 ClassTemplateDecl *NewTemplate
1632 = ClassTemplateDecl::Create(Context, SemanticContext, NameLoc,
1633 DeclarationName(Name), TemplateParams,
1636 if (ShouldAddRedecl)
1637 NewTemplate->setPreviousDecl(PrevClassTemplate);
1639 NewClass->setDescribedClassTemplate(NewTemplate);
1641 if (ModulePrivateLoc.isValid())
1642 NewTemplate->setModulePrivate();
1644 // Build the type for the class template declaration now.
1645 QualType T = NewTemplate->getInjectedClassNameSpecialization();
1646 T = Context.getInjectedClassNameType(NewClass, T);
1647 assert(T->isDependentType() && "Class template type is not dependent?");
1650 // If we are providing an explicit specialization of a member that is a
1651 // class template, make a note of that.
1652 if (PrevClassTemplate &&
1653 PrevClassTemplate->getInstantiatedFromMemberTemplate())
1654 PrevClassTemplate->setMemberSpecialization();
1656 // Set the access specifier.
1657 if (!Invalid && TUK != TUK_Friend && NewTemplate->getDeclContext()->isRecord())
1658 SetMemberAccessSpecifier(NewTemplate, PrevClassTemplate, AS);
1660 // Set the lexical context of these templates
1661 NewClass->setLexicalDeclContext(CurContext);
1662 NewTemplate->setLexicalDeclContext(CurContext);
1664 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
1665 NewClass->startDefinition();
1667 ProcessDeclAttributeList(S, NewClass, Attr);
1669 if (PrevClassTemplate)
1670 mergeDeclAttributes(NewClass, PrevClassTemplate->getTemplatedDecl());
1672 AddPushedVisibilityAttribute(NewClass);
1673 inferGslOwnerPointerAttribute(NewClass);
1675 if (TUK != TUK_Friend) {
1676 // Per C++ [basic.scope.temp]p2, skip the template parameter scopes.
1678 while ((Outer->getFlags() & Scope::TemplateParamScope) != 0)
1679 Outer = Outer->getParent();
1680 PushOnScopeChains(NewTemplate, Outer);
1682 if (PrevClassTemplate && PrevClassTemplate->getAccess() != AS_none) {
1683 NewTemplate->setAccess(PrevClassTemplate->getAccess());
1684 NewClass->setAccess(PrevClassTemplate->getAccess());
1687 NewTemplate->setObjectOfFriendDecl();
1689 // Friend templates are visible in fairly strange ways.
1690 if (!CurContext->isDependentContext()) {
1691 DeclContext *DC = SemanticContext->getRedeclContext();
1692 DC->makeDeclVisibleInContext(NewTemplate);
1693 if (Scope *EnclosingScope = getScopeForDeclContext(S, DC))
1694 PushOnScopeChains(NewTemplate, EnclosingScope,
1695 /* AddToContext = */ false);
1698 FriendDecl *Friend = FriendDecl::Create(
1699 Context, CurContext, NewClass->getLocation(), NewTemplate, FriendLoc);
1700 Friend->setAccess(AS_public);
1701 CurContext->addDecl(Friend);
1704 if (PrevClassTemplate)
1705 CheckRedeclarationModuleOwnership(NewTemplate, PrevClassTemplate);
1708 NewTemplate->setInvalidDecl();
1709 NewClass->setInvalidDecl();
1712 ActOnDocumentableDecl(NewTemplate);
1714 if (SkipBody && SkipBody->ShouldSkip)
1715 return SkipBody->Previous;
1721 /// Tree transform to "extract" a transformed type from a class template's
1722 /// constructor to a deduction guide.
1723 class ExtractTypeForDeductionGuide
1724 : public TreeTransform<ExtractTypeForDeductionGuide> {
1726 typedef TreeTransform<ExtractTypeForDeductionGuide> Base;
1727 ExtractTypeForDeductionGuide(Sema &SemaRef) : Base(SemaRef) {}
1729 TypeSourceInfo *transform(TypeSourceInfo *TSI) { return TransformType(TSI); }
1731 QualType TransformTypedefType(TypeLocBuilder &TLB, TypedefTypeLoc TL) {
1732 return TransformType(
1734 TL.getTypedefNameDecl()->getTypeSourceInfo()->getTypeLoc());
1738 /// Transform to convert portions of a constructor declaration into the
1739 /// corresponding deduction guide, per C++1z [over.match.class.deduct]p1.
1740 struct ConvertConstructorToDeductionGuideTransform {
1741 ConvertConstructorToDeductionGuideTransform(Sema &S,
1742 ClassTemplateDecl *Template)
1743 : SemaRef(S), Template(Template) {}
1746 ClassTemplateDecl *Template;
1748 DeclContext *DC = Template->getDeclContext();
1749 CXXRecordDecl *Primary = Template->getTemplatedDecl();
1750 DeclarationName DeductionGuideName =
1751 SemaRef.Context.DeclarationNames.getCXXDeductionGuideName(Template);
1753 QualType DeducedType = SemaRef.Context.getTypeDeclType(Primary);
1755 // Index adjustment to apply to convert depth-1 template parameters into
1756 // depth-0 template parameters.
1757 unsigned Depth1IndexAdjustment = Template->getTemplateParameters()->size();
1759 /// Transform a constructor declaration into a deduction guide.
1760 NamedDecl *transformConstructor(FunctionTemplateDecl *FTD,
1761 CXXConstructorDecl *CD) {
1762 SmallVector<TemplateArgument, 16> SubstArgs;
1764 LocalInstantiationScope Scope(SemaRef);
1766 // C++ [over.match.class.deduct]p1:
1767 // -- For each constructor of the class template designated by the
1768 // template-name, a function template with the following properties:
1770 // -- The template parameters are the template parameters of the class
1771 // template followed by the template parameters (including default
1772 // template arguments) of the constructor, if any.
1773 TemplateParameterList *TemplateParams = Template->getTemplateParameters();
1775 TemplateParameterList *InnerParams = FTD->getTemplateParameters();
1776 SmallVector<NamedDecl *, 16> AllParams;
1777 AllParams.reserve(TemplateParams->size() + InnerParams->size());
1778 AllParams.insert(AllParams.begin(),
1779 TemplateParams->begin(), TemplateParams->end());
1780 SubstArgs.reserve(InnerParams->size());
1782 // Later template parameters could refer to earlier ones, so build up
1783 // a list of substituted template arguments as we go.
1784 for (NamedDecl *Param : *InnerParams) {
1785 MultiLevelTemplateArgumentList Args;
1786 Args.addOuterTemplateArguments(SubstArgs);
1787 Args.addOuterRetainedLevel();
1788 NamedDecl *NewParam = transformTemplateParameter(Param, Args);
1791 AllParams.push_back(NewParam);
1792 SubstArgs.push_back(SemaRef.Context.getCanonicalTemplateArgument(
1793 SemaRef.Context.getInjectedTemplateArg(NewParam)));
1795 TemplateParams = TemplateParameterList::Create(
1796 SemaRef.Context, InnerParams->getTemplateLoc(),
1797 InnerParams->getLAngleLoc(), AllParams, InnerParams->getRAngleLoc(),
1798 /*FIXME: RequiresClause*/ nullptr);
1801 // If we built a new template-parameter-list, track that we need to
1802 // substitute references to the old parameters into references to the
1804 MultiLevelTemplateArgumentList Args;
1806 Args.addOuterTemplateArguments(SubstArgs);
1807 Args.addOuterRetainedLevel();
1810 FunctionProtoTypeLoc FPTL = CD->getTypeSourceInfo()->getTypeLoc()
1811 .getAsAdjusted<FunctionProtoTypeLoc>();
1812 assert(FPTL && "no prototype for constructor declaration");
1814 // Transform the type of the function, adjusting the return type and
1815 // replacing references to the old parameters with references to the
1818 SmallVector<ParmVarDecl*, 8> Params;
1819 QualType NewType = transformFunctionProtoType(TLB, FPTL, Params, Args);
1820 if (NewType.isNull())
1822 TypeSourceInfo *NewTInfo = TLB.getTypeSourceInfo(SemaRef.Context, NewType);
1824 return buildDeductionGuide(TemplateParams, CD->getExplicitSpecifier(),
1825 NewTInfo, CD->getBeginLoc(), CD->getLocation(),
1829 /// Build a deduction guide with the specified parameter types.
1830 NamedDecl *buildSimpleDeductionGuide(MutableArrayRef<QualType> ParamTypes) {
1831 SourceLocation Loc = Template->getLocation();
1833 // Build the requested type.
1834 FunctionProtoType::ExtProtoInfo EPI;
1835 EPI.HasTrailingReturn = true;
1836 QualType Result = SemaRef.BuildFunctionType(DeducedType, ParamTypes, Loc,
1837 DeductionGuideName, EPI);
1838 TypeSourceInfo *TSI = SemaRef.Context.getTrivialTypeSourceInfo(Result, Loc);
1840 FunctionProtoTypeLoc FPTL =
1841 TSI->getTypeLoc().castAs<FunctionProtoTypeLoc>();
1843 // Build the parameters, needed during deduction / substitution.
1844 SmallVector<ParmVarDecl*, 4> Params;
1845 for (auto T : ParamTypes) {
1846 ParmVarDecl *NewParam = ParmVarDecl::Create(
1847 SemaRef.Context, DC, Loc, Loc, nullptr, T,
1848 SemaRef.Context.getTrivialTypeSourceInfo(T, Loc), SC_None, nullptr);
1849 NewParam->setScopeInfo(0, Params.size());
1850 FPTL.setParam(Params.size(), NewParam);
1851 Params.push_back(NewParam);
1854 return buildDeductionGuide(Template->getTemplateParameters(),
1855 ExplicitSpecifier(), TSI, Loc, Loc, Loc);
1859 /// Transform a constructor template parameter into a deduction guide template
1860 /// parameter, rebuilding any internal references to earlier parameters and
1861 /// renumbering as we go.
1862 NamedDecl *transformTemplateParameter(NamedDecl *TemplateParam,
1863 MultiLevelTemplateArgumentList &Args) {
1864 if (auto *TTP = dyn_cast<TemplateTypeParmDecl>(TemplateParam)) {
1865 // TemplateTypeParmDecl's index cannot be changed after creation, so
1866 // substitute it directly.
1867 auto *NewTTP = TemplateTypeParmDecl::Create(
1868 SemaRef.Context, DC, TTP->getBeginLoc(), TTP->getLocation(),
1869 /*Depth*/ 0, Depth1IndexAdjustment + TTP->getIndex(),
1870 TTP->getIdentifier(), TTP->wasDeclaredWithTypename(),
1871 TTP->isParameterPack());
1872 if (TTP->hasDefaultArgument()) {
1873 TypeSourceInfo *InstantiatedDefaultArg =
1874 SemaRef.SubstType(TTP->getDefaultArgumentInfo(), Args,
1875 TTP->getDefaultArgumentLoc(), TTP->getDeclName());
1876 if (InstantiatedDefaultArg)
1877 NewTTP->setDefaultArgument(InstantiatedDefaultArg);
1879 SemaRef.CurrentInstantiationScope->InstantiatedLocal(TemplateParam,
1884 if (auto *TTP = dyn_cast<TemplateTemplateParmDecl>(TemplateParam))
1885 return transformTemplateParameterImpl(TTP, Args);
1887 return transformTemplateParameterImpl(
1888 cast<NonTypeTemplateParmDecl>(TemplateParam), Args);
1890 template<typename TemplateParmDecl>
1892 transformTemplateParameterImpl(TemplateParmDecl *OldParam,
1893 MultiLevelTemplateArgumentList &Args) {
1894 // Ask the template instantiator to do the heavy lifting for us, then adjust
1895 // the index of the parameter once it's done.
1897 cast_or_null<TemplateParmDecl>(SemaRef.SubstDecl(OldParam, DC, Args));
1898 assert(NewParam->getDepth() == 0 && "unexpected template param depth");
1899 NewParam->setPosition(NewParam->getPosition() + Depth1IndexAdjustment);
1903 QualType transformFunctionProtoType(TypeLocBuilder &TLB,
1904 FunctionProtoTypeLoc TL,
1905 SmallVectorImpl<ParmVarDecl*> &Params,
1906 MultiLevelTemplateArgumentList &Args) {
1907 SmallVector<QualType, 4> ParamTypes;
1908 const FunctionProtoType *T = TL.getTypePtr();
1910 // -- The types of the function parameters are those of the constructor.
1911 for (auto *OldParam : TL.getParams()) {
1912 ParmVarDecl *NewParam = transformFunctionTypeParam(OldParam, Args);
1915 ParamTypes.push_back(NewParam->getType());
1916 Params.push_back(NewParam);
1919 // -- The return type is the class template specialization designated by
1920 // the template-name and template arguments corresponding to the
1921 // template parameters obtained from the class template.
1923 // We use the injected-class-name type of the primary template instead.
1924 // This has the convenient property that it is different from any type that
1925 // the user can write in a deduction-guide (because they cannot enter the
1926 // context of the template), so implicit deduction guides can never collide
1927 // with explicit ones.
1928 QualType ReturnType = DeducedType;
1929 TLB.pushTypeSpec(ReturnType).setNameLoc(Primary->getLocation());
1931 // Resolving a wording defect, we also inherit the variadicness of the
1933 FunctionProtoType::ExtProtoInfo EPI;
1934 EPI.Variadic = T->isVariadic();
1935 EPI.HasTrailingReturn = true;
1937 QualType Result = SemaRef.BuildFunctionType(
1938 ReturnType, ParamTypes, TL.getBeginLoc(), DeductionGuideName, EPI);
1939 if (Result.isNull())
1942 FunctionProtoTypeLoc NewTL = TLB.push<FunctionProtoTypeLoc>(Result);
1943 NewTL.setLocalRangeBegin(TL.getLocalRangeBegin());
1944 NewTL.setLParenLoc(TL.getLParenLoc());
1945 NewTL.setRParenLoc(TL.getRParenLoc());
1946 NewTL.setExceptionSpecRange(SourceRange());
1947 NewTL.setLocalRangeEnd(TL.getLocalRangeEnd());
1948 for (unsigned I = 0, E = NewTL.getNumParams(); I != E; ++I)
1949 NewTL.setParam(I, Params[I]);
1955 transformFunctionTypeParam(ParmVarDecl *OldParam,
1956 MultiLevelTemplateArgumentList &Args) {
1957 TypeSourceInfo *OldDI = OldParam->getTypeSourceInfo();
1958 TypeSourceInfo *NewDI;
1959 if (auto PackTL = OldDI->getTypeLoc().getAs<PackExpansionTypeLoc>()) {
1960 // Expand out the one and only element in each inner pack.
1961 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(SemaRef, 0);
1963 SemaRef.SubstType(PackTL.getPatternLoc(), Args,
1964 OldParam->getLocation(), OldParam->getDeclName());
1965 if (!NewDI) return nullptr;
1967 SemaRef.CheckPackExpansion(NewDI, PackTL.getEllipsisLoc(),
1968 PackTL.getTypePtr()->getNumExpansions());
1970 NewDI = SemaRef.SubstType(OldDI, Args, OldParam->getLocation(),
1971 OldParam->getDeclName());
1975 // Extract the type. This (for instance) replaces references to typedef
1976 // members of the current instantiations with the definitions of those
1977 // typedefs, avoiding triggering instantiation of the deduced type during
1979 NewDI = ExtractTypeForDeductionGuide(SemaRef).transform(NewDI);
1981 // Resolving a wording defect, we also inherit default arguments from the
1983 ExprResult NewDefArg;
1984 if (OldParam->hasDefaultArg()) {
1985 NewDefArg = SemaRef.SubstExpr(OldParam->getDefaultArg(), Args);
1986 if (NewDefArg.isInvalid())
1990 ParmVarDecl *NewParam = ParmVarDecl::Create(SemaRef.Context, DC,
1991 OldParam->getInnerLocStart(),
1992 OldParam->getLocation(),
1993 OldParam->getIdentifier(),
1996 OldParam->getStorageClass(),
1998 NewParam->setScopeInfo(OldParam->getFunctionScopeDepth(),
1999 OldParam->getFunctionScopeIndex());
2000 SemaRef.CurrentInstantiationScope->InstantiatedLocal(OldParam, NewParam);
2004 NamedDecl *buildDeductionGuide(TemplateParameterList *TemplateParams,
2005 ExplicitSpecifier ES, TypeSourceInfo *TInfo,
2006 SourceLocation LocStart, SourceLocation Loc,
2007 SourceLocation LocEnd) {
2008 DeclarationNameInfo Name(DeductionGuideName, Loc);
2009 ArrayRef<ParmVarDecl *> Params =
2010 TInfo->getTypeLoc().castAs<FunctionProtoTypeLoc>().getParams();
2012 // Build the implicit deduction guide template.
2014 CXXDeductionGuideDecl::Create(SemaRef.Context, DC, LocStart, ES, Name,
2015 TInfo->getType(), TInfo, LocEnd);
2016 Guide->setImplicit();
2017 Guide->setParams(Params);
2019 for (auto *Param : Params)
2020 Param->setDeclContext(Guide);
2022 auto *GuideTemplate = FunctionTemplateDecl::Create(
2023 SemaRef.Context, DC, Loc, DeductionGuideName, TemplateParams, Guide);
2024 GuideTemplate->setImplicit();
2025 Guide->setDescribedFunctionTemplate(GuideTemplate);
2027 if (isa<CXXRecordDecl>(DC)) {
2028 Guide->setAccess(AS_public);
2029 GuideTemplate->setAccess(AS_public);
2032 DC->addDecl(GuideTemplate);
2033 return GuideTemplate;
2038 void Sema::DeclareImplicitDeductionGuides(TemplateDecl *Template,
2039 SourceLocation Loc) {
2040 if (CXXRecordDecl *DefRecord =
2041 cast<CXXRecordDecl>(Template->getTemplatedDecl())->getDefinition()) {
2042 TemplateDecl *DescribedTemplate = DefRecord->getDescribedClassTemplate();
2043 Template = DescribedTemplate ? DescribedTemplate : Template;
2046 DeclContext *DC = Template->getDeclContext();
2047 if (DC->isDependentContext())
2050 ConvertConstructorToDeductionGuideTransform Transform(
2051 *this, cast<ClassTemplateDecl>(Template));
2052 if (!isCompleteType(Loc, Transform.DeducedType))
2055 // Check whether we've already declared deduction guides for this template.
2056 // FIXME: Consider storing a flag on the template to indicate this.
2057 auto Existing = DC->lookup(Transform.DeductionGuideName);
2058 for (auto *D : Existing)
2059 if (D->isImplicit())
2062 // In case we were expanding a pack when we attempted to declare deduction
2063 // guides, turn off pack expansion for everything we're about to do.
2064 ArgumentPackSubstitutionIndexRAII SubstIndex(*this, -1);
2065 // Create a template instantiation record to track the "instantiation" of
2066 // constructors into deduction guides.
2067 // FIXME: Add a kind for this to give more meaningful diagnostics. But can
2068 // this substitution process actually fail?
2069 InstantiatingTemplate BuildingDeductionGuides(*this, Loc, Template);
2070 if (BuildingDeductionGuides.isInvalid())
2073 // Convert declared constructors into deduction guide templates.
2074 // FIXME: Skip constructors for which deduction must necessarily fail (those
2075 // for which some class template parameter without a default argument never
2076 // appears in a deduced context).
2077 bool AddedAny = false;
2078 for (NamedDecl *D : LookupConstructors(Transform.Primary)) {
2079 D = D->getUnderlyingDecl();
2080 if (D->isInvalidDecl() || D->isImplicit())
2082 D = cast<NamedDecl>(D->getCanonicalDecl());
2084 auto *FTD = dyn_cast<FunctionTemplateDecl>(D);
2086 dyn_cast_or_null<CXXConstructorDecl>(FTD ? FTD->getTemplatedDecl() : D);
2087 // Class-scope explicit specializations (MS extension) do not result in
2088 // deduction guides.
2089 if (!CD || (!FTD && CD->isFunctionTemplateSpecialization()))
2092 Transform.transformConstructor(FTD, CD);
2096 // C++17 [over.match.class.deduct]
2097 // -- If C is not defined or does not declare any constructors, an
2098 // additional function template derived as above from a hypothetical
2101 Transform.buildSimpleDeductionGuide(None);
2103 // -- An additional function template derived as above from a hypothetical
2104 // constructor C(C), called the copy deduction candidate.
2105 cast<CXXDeductionGuideDecl>(
2106 cast<FunctionTemplateDecl>(
2107 Transform.buildSimpleDeductionGuide(Transform.DeducedType))
2108 ->getTemplatedDecl())
2109 ->setIsCopyDeductionCandidate();
2112 /// Diagnose the presence of a default template argument on a
2113 /// template parameter, which is ill-formed in certain contexts.
2115 /// \returns true if the default template argument should be dropped.
2116 static bool DiagnoseDefaultTemplateArgument(Sema &S,
2117 Sema::TemplateParamListContext TPC,
2118 SourceLocation ParamLoc,
2119 SourceRange DefArgRange) {
2121 case Sema::TPC_ClassTemplate:
2122 case Sema::TPC_VarTemplate:
2123 case Sema::TPC_TypeAliasTemplate:
2126 case Sema::TPC_FunctionTemplate:
2127 case Sema::TPC_FriendFunctionTemplateDefinition:
2128 // C++ [temp.param]p9:
2129 // A default template-argument shall not be specified in a
2130 // function template declaration or a function template
2132 // If a friend function template declaration specifies a default
2133 // template-argument, that declaration shall be a definition and shall be
2134 // the only declaration of the function template in the translation unit.
2135 // (C++98/03 doesn't have this wording; see DR226).
2136 S.Diag(ParamLoc, S.getLangOpts().CPlusPlus11 ?
2137 diag::warn_cxx98_compat_template_parameter_default_in_function_template
2138 : diag::ext_template_parameter_default_in_function_template)
2142 case Sema::TPC_ClassTemplateMember:
2143 // C++0x [temp.param]p9:
2144 // A default template-argument shall not be specified in the
2145 // template-parameter-lists of the definition of a member of a
2146 // class template that appears outside of the member's class.
2147 S.Diag(ParamLoc, diag::err_template_parameter_default_template_member)
2151 case Sema::TPC_FriendClassTemplate:
2152 case Sema::TPC_FriendFunctionTemplate:
2153 // C++ [temp.param]p9:
2154 // A default template-argument shall not be specified in a
2155 // friend template declaration.
2156 S.Diag(ParamLoc, diag::err_template_parameter_default_friend_template)
2160 // FIXME: C++0x [temp.param]p9 allows default template-arguments
2161 // for friend function templates if there is only a single
2162 // declaration (and it is a definition). Strange!
2165 llvm_unreachable("Invalid TemplateParamListContext!");
2168 /// Check for unexpanded parameter packs within the template parameters
2169 /// of a template template parameter, recursively.
2170 static bool DiagnoseUnexpandedParameterPacks(Sema &S,
2171 TemplateTemplateParmDecl *TTP) {
2172 // A template template parameter which is a parameter pack is also a pack
2174 if (TTP->isParameterPack())
2177 TemplateParameterList *Params = TTP->getTemplateParameters();
2178 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
2179 NamedDecl *P = Params->getParam(I);
2180 if (NonTypeTemplateParmDecl *NTTP = dyn_cast<NonTypeTemplateParmDecl>(P)) {
2181 if (!NTTP->isParameterPack() &&
2182 S.DiagnoseUnexpandedParameterPack(NTTP->getLocation(),
2183 NTTP->getTypeSourceInfo(),
2184 Sema::UPPC_NonTypeTemplateParameterType))
2190 if (TemplateTemplateParmDecl *InnerTTP
2191 = dyn_cast<TemplateTemplateParmDecl>(P))
2192 if (DiagnoseUnexpandedParameterPacks(S, InnerTTP))
2199 /// Checks the validity of a template parameter list, possibly
2200 /// considering the template parameter list from a previous
2203 /// If an "old" template parameter list is provided, it must be
2204 /// equivalent (per TemplateParameterListsAreEqual) to the "new"
2205 /// template parameter list.
2207 /// \param NewParams Template parameter list for a new template
2208 /// declaration. This template parameter list will be updated with any
2209 /// default arguments that are carried through from the previous
2210 /// template parameter list.
2212 /// \param OldParams If provided, template parameter list from a
2213 /// previous declaration of the same template. Default template
2214 /// arguments will be merged from the old template parameter list to
2215 /// the new template parameter list.
2217 /// \param TPC Describes the context in which we are checking the given
2218 /// template parameter list.
2220 /// \param SkipBody If we might have already made a prior merged definition
2221 /// of this template visible, the corresponding body-skipping information.
2222 /// Default argument redefinition is not an error when skipping such a body,
2223 /// because (under the ODR) we can assume the default arguments are the same
2224 /// as the prior merged definition.
2226 /// \returns true if an error occurred, false otherwise.
2227 bool Sema::CheckTemplateParameterList(TemplateParameterList *NewParams,
2228 TemplateParameterList *OldParams,
2229 TemplateParamListContext TPC,
2230 SkipBodyInfo *SkipBody) {
2231 bool Invalid = false;
2233 // C++ [temp.param]p10:
2234 // The set of default template-arguments available for use with a
2235 // template declaration or definition is obtained by merging the
2236 // default arguments from the definition (if in scope) and all
2237 // declarations in scope in the same way default function
2238 // arguments are (8.3.6).
2239 bool SawDefaultArgument = false;
2240 SourceLocation PreviousDefaultArgLoc;
2242 // Dummy initialization to avoid warnings.
2243 TemplateParameterList::iterator OldParam = NewParams->end();
2245 OldParam = OldParams->begin();
2247 bool RemoveDefaultArguments = false;
2248 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2249 NewParamEnd = NewParams->end();
2250 NewParam != NewParamEnd; ++NewParam) {
2251 // Variables used to diagnose redundant default arguments
2252 bool RedundantDefaultArg = false;
2253 SourceLocation OldDefaultLoc;
2254 SourceLocation NewDefaultLoc;
2256 // Variable used to diagnose missing default arguments
2257 bool MissingDefaultArg = false;
2259 // Variable used to diagnose non-final parameter packs
2260 bool SawParameterPack = false;
2262 if (TemplateTypeParmDecl *NewTypeParm
2263 = dyn_cast<TemplateTypeParmDecl>(*NewParam)) {
2264 // Check the presence of a default argument here.
2265 if (NewTypeParm->hasDefaultArgument() &&
2266 DiagnoseDefaultTemplateArgument(*this, TPC,
2267 NewTypeParm->getLocation(),
2268 NewTypeParm->getDefaultArgumentInfo()->getTypeLoc()
2270 NewTypeParm->removeDefaultArgument();
2272 // Merge default arguments for template type parameters.
2273 TemplateTypeParmDecl *OldTypeParm
2274 = OldParams? cast<TemplateTypeParmDecl>(*OldParam) : nullptr;
2275 if (NewTypeParm->isParameterPack()) {
2276 assert(!NewTypeParm->hasDefaultArgument() &&
2277 "Parameter packs can't have a default argument!");
2278 SawParameterPack = true;
2279 } else if (OldTypeParm && hasVisibleDefaultArgument(OldTypeParm) &&
2280 NewTypeParm->hasDefaultArgument() &&
2281 (!SkipBody || !SkipBody->ShouldSkip)) {
2282 OldDefaultLoc = OldTypeParm->getDefaultArgumentLoc();
2283 NewDefaultLoc = NewTypeParm->getDefaultArgumentLoc();
2284 SawDefaultArgument = true;
2285 RedundantDefaultArg = true;
2286 PreviousDefaultArgLoc = NewDefaultLoc;
2287 } else if (OldTypeParm && OldTypeParm->hasDefaultArgument()) {
2288 // Merge the default argument from the old declaration to the
2290 NewTypeParm->setInheritedDefaultArgument(Context, OldTypeParm);
2291 PreviousDefaultArgLoc = OldTypeParm->getDefaultArgumentLoc();
2292 } else if (NewTypeParm->hasDefaultArgument()) {
2293 SawDefaultArgument = true;
2294 PreviousDefaultArgLoc = NewTypeParm->getDefaultArgumentLoc();
2295 } else if (SawDefaultArgument)
2296 MissingDefaultArg = true;
2297 } else if (NonTypeTemplateParmDecl *NewNonTypeParm
2298 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam)) {
2299 // Check for unexpanded parameter packs.
2300 if (!NewNonTypeParm->isParameterPack() &&
2301 DiagnoseUnexpandedParameterPack(NewNonTypeParm->getLocation(),
2302 NewNonTypeParm->getTypeSourceInfo(),
2303 UPPC_NonTypeTemplateParameterType)) {
2308 // Check the presence of a default argument here.
2309 if (NewNonTypeParm->hasDefaultArgument() &&
2310 DiagnoseDefaultTemplateArgument(*this, TPC,
2311 NewNonTypeParm->getLocation(),
2312 NewNonTypeParm->getDefaultArgument()->getSourceRange())) {
2313 NewNonTypeParm->removeDefaultArgument();
2316 // Merge default arguments for non-type template parameters
2317 NonTypeTemplateParmDecl *OldNonTypeParm
2318 = OldParams? cast<NonTypeTemplateParmDecl>(*OldParam) : nullptr;
2319 if (NewNonTypeParm->isParameterPack()) {
2320 assert(!NewNonTypeParm->hasDefaultArgument() &&
2321 "Parameter packs can't have a default argument!");
2322 if (!NewNonTypeParm->isPackExpansion())
2323 SawParameterPack = true;
2324 } else if (OldNonTypeParm && hasVisibleDefaultArgument(OldNonTypeParm) &&
2325 NewNonTypeParm->hasDefaultArgument() &&
2326 (!SkipBody || !SkipBody->ShouldSkip)) {
2327 OldDefaultLoc = OldNonTypeParm->getDefaultArgumentLoc();
2328 NewDefaultLoc = NewNonTypeParm->getDefaultArgumentLoc();
2329 SawDefaultArgument = true;
2330 RedundantDefaultArg = true;
2331 PreviousDefaultArgLoc = NewDefaultLoc;
2332 } else if (OldNonTypeParm && OldNonTypeParm->hasDefaultArgument()) {
2333 // Merge the default argument from the old declaration to the
2335 NewNonTypeParm->setInheritedDefaultArgument(Context, OldNonTypeParm);
2336 PreviousDefaultArgLoc = OldNonTypeParm->getDefaultArgumentLoc();
2337 } else if (NewNonTypeParm->hasDefaultArgument()) {
2338 SawDefaultArgument = true;
2339 PreviousDefaultArgLoc = NewNonTypeParm->getDefaultArgumentLoc();
2340 } else if (SawDefaultArgument)
2341 MissingDefaultArg = true;
2343 TemplateTemplateParmDecl *NewTemplateParm
2344 = cast<TemplateTemplateParmDecl>(*NewParam);
2346 // Check for unexpanded parameter packs, recursively.
2347 if (::DiagnoseUnexpandedParameterPacks(*this, NewTemplateParm)) {
2352 // Check the presence of a default argument here.
2353 if (NewTemplateParm->hasDefaultArgument() &&
2354 DiagnoseDefaultTemplateArgument(*this, TPC,
2355 NewTemplateParm->getLocation(),
2356 NewTemplateParm->getDefaultArgument().getSourceRange()))
2357 NewTemplateParm->removeDefaultArgument();
2359 // Merge default arguments for template template parameters
2360 TemplateTemplateParmDecl *OldTemplateParm
2361 = OldParams? cast<TemplateTemplateParmDecl>(*OldParam) : nullptr;
2362 if (NewTemplateParm->isParameterPack()) {
2363 assert(!NewTemplateParm->hasDefaultArgument() &&
2364 "Parameter packs can't have a default argument!");
2365 if (!NewTemplateParm->isPackExpansion())
2366 SawParameterPack = true;
2367 } else if (OldTemplateParm &&
2368 hasVisibleDefaultArgument(OldTemplateParm) &&
2369 NewTemplateParm->hasDefaultArgument() &&
2370 (!SkipBody || !SkipBody->ShouldSkip)) {
2371 OldDefaultLoc = OldTemplateParm->getDefaultArgument().getLocation();
2372 NewDefaultLoc = NewTemplateParm->getDefaultArgument().getLocation();
2373 SawDefaultArgument = true;
2374 RedundantDefaultArg = true;
2375 PreviousDefaultArgLoc = NewDefaultLoc;
2376 } else if (OldTemplateParm && OldTemplateParm->hasDefaultArgument()) {
2377 // Merge the default argument from the old declaration to the
2379 NewTemplateParm->setInheritedDefaultArgument(Context, OldTemplateParm);
2380 PreviousDefaultArgLoc
2381 = OldTemplateParm->getDefaultArgument().getLocation();
2382 } else if (NewTemplateParm->hasDefaultArgument()) {
2383 SawDefaultArgument = true;
2384 PreviousDefaultArgLoc
2385 = NewTemplateParm->getDefaultArgument().getLocation();
2386 } else if (SawDefaultArgument)
2387 MissingDefaultArg = true;
2390 // C++11 [temp.param]p11:
2391 // If a template parameter of a primary class template or alias template
2392 // is a template parameter pack, it shall be the last template parameter.
2393 if (SawParameterPack && (NewParam + 1) != NewParamEnd &&
2394 (TPC == TPC_ClassTemplate || TPC == TPC_VarTemplate ||
2395 TPC == TPC_TypeAliasTemplate)) {
2396 Diag((*NewParam)->getLocation(),
2397 diag::err_template_param_pack_must_be_last_template_parameter);
2401 if (RedundantDefaultArg) {
2402 // C++ [temp.param]p12:
2403 // A template-parameter shall not be given default arguments
2404 // by two different declarations in the same scope.
2405 Diag(NewDefaultLoc, diag::err_template_param_default_arg_redefinition);
2406 Diag(OldDefaultLoc, diag::note_template_param_prev_default_arg);
2408 } else if (MissingDefaultArg && TPC != TPC_FunctionTemplate) {
2409 // C++ [temp.param]p11:
2410 // If a template-parameter of a class template has a default
2411 // template-argument, each subsequent template-parameter shall either
2412 // have a default template-argument supplied or be a template parameter
2414 Diag((*NewParam)->getLocation(),
2415 diag::err_template_param_default_arg_missing);
2416 Diag(PreviousDefaultArgLoc, diag::note_template_param_prev_default_arg);
2418 RemoveDefaultArguments = true;
2421 // If we have an old template parameter list that we're merging
2422 // in, move on to the next parameter.
2427 // We were missing some default arguments at the end of the list, so remove
2428 // all of the default arguments.
2429 if (RemoveDefaultArguments) {
2430 for (TemplateParameterList::iterator NewParam = NewParams->begin(),
2431 NewParamEnd = NewParams->end();
2432 NewParam != NewParamEnd; ++NewParam) {
2433 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*NewParam))
2434 TTP->removeDefaultArgument();
2435 else if (NonTypeTemplateParmDecl *NTTP
2436 = dyn_cast<NonTypeTemplateParmDecl>(*NewParam))
2437 NTTP->removeDefaultArgument();
2439 cast<TemplateTemplateParmDecl>(*NewParam)->removeDefaultArgument();
2448 /// A class which looks for a use of a certain level of template
2450 struct DependencyChecker : RecursiveASTVisitor<DependencyChecker> {
2451 typedef RecursiveASTVisitor<DependencyChecker> super;
2455 // Whether we're looking for a use of a template parameter that makes the
2456 // overall construct type-dependent / a dependent type. This is strictly
2457 // best-effort for now; we may fail to match at all for a dependent type
2458 // in some cases if this is set.
2459 bool IgnoreNonTypeDependent;
2462 SourceLocation MatchLoc;
2464 DependencyChecker(unsigned Depth, bool IgnoreNonTypeDependent)
2465 : Depth(Depth), IgnoreNonTypeDependent(IgnoreNonTypeDependent),
2468 DependencyChecker(TemplateParameterList *Params, bool IgnoreNonTypeDependent)
2469 : IgnoreNonTypeDependent(IgnoreNonTypeDependent), Match(false) {
2470 NamedDecl *ND = Params->getParam(0);
2471 if (TemplateTypeParmDecl *PD = dyn_cast<TemplateTypeParmDecl>(ND)) {
2472 Depth = PD->getDepth();
2473 } else if (NonTypeTemplateParmDecl *PD =
2474 dyn_cast<NonTypeTemplateParmDecl>(ND)) {
2475 Depth = PD->getDepth();
2477 Depth = cast<TemplateTemplateParmDecl>(ND)->getDepth();
2481 bool Matches(unsigned ParmDepth, SourceLocation Loc = SourceLocation()) {
2482 if (ParmDepth >= Depth) {
2490 bool TraverseStmt(Stmt *S, DataRecursionQueue *Q = nullptr) {
2491 // Prune out non-type-dependent expressions if requested. This can
2492 // sometimes result in us failing to find a template parameter reference
2493 // (if a value-dependent expression creates a dependent type), but this
2494 // mode is best-effort only.
2495 if (auto *E = dyn_cast_or_null<Expr>(S))
2496 if (IgnoreNonTypeDependent && !E->isTypeDependent())
2498 return super::TraverseStmt(S, Q);
2501 bool TraverseTypeLoc(TypeLoc TL) {
2502 if (IgnoreNonTypeDependent && !TL.isNull() &&
2503 !TL.getType()->isDependentType())
2505 return super::TraverseTypeLoc(TL);
2508 bool VisitTemplateTypeParmTypeLoc(TemplateTypeParmTypeLoc TL) {
2509 return !Matches(TL.getTypePtr()->getDepth(), TL.getNameLoc());
2512 bool VisitTemplateTypeParmType(const TemplateTypeParmType *T) {
2513 // For a best-effort search, keep looking until we find a location.
2514 return IgnoreNonTypeDependent || !Matches(T->getDepth());
2517 bool TraverseTemplateName(TemplateName N) {
2518 if (TemplateTemplateParmDecl *PD =
2519 dyn_cast_or_null<TemplateTemplateParmDecl>(N.getAsTemplateDecl()))
2520 if (Matches(PD->getDepth()))
2522 return super::TraverseTemplateName(N);
2525 bool VisitDeclRefExpr(DeclRefExpr *E) {
2526 if (NonTypeTemplateParmDecl *PD =
2527 dyn_cast<NonTypeTemplateParmDecl>(E->getDecl()))
2528 if (Matches(PD->getDepth(), E->getExprLoc()))
2530 return super::VisitDeclRefExpr(E);
2533 bool VisitSubstTemplateTypeParmType(const SubstTemplateTypeParmType *T) {
2534 return TraverseType(T->getReplacementType());
2538 VisitSubstTemplateTypeParmPackType(const SubstTemplateTypeParmPackType *T) {
2539 return TraverseTemplateArgument(T->getArgumentPack());
2542 bool TraverseInjectedClassNameType(const InjectedClassNameType *T) {
2543 return TraverseType(T->getInjectedSpecializationType());
2546 } // end anonymous namespace
2548 /// Determines whether a given type depends on the given parameter
2551 DependsOnTemplateParameters(QualType T, TemplateParameterList *Params) {
2552 DependencyChecker Checker(Params, /*IgnoreNonTypeDependent*/false);
2553 Checker.TraverseType(T);
2554 return Checker.Match;
2557 // Find the source range corresponding to the named type in the given
2558 // nested-name-specifier, if any.
2559 static SourceRange getRangeOfTypeInNestedNameSpecifier(ASTContext &Context,
2561 const CXXScopeSpec &SS) {
2562 NestedNameSpecifierLoc NNSLoc(SS.getScopeRep(), SS.location_data());
2563 while (NestedNameSpecifier *NNS = NNSLoc.getNestedNameSpecifier()) {
2564 if (const Type *CurType = NNS->getAsType()) {
2565 if (Context.hasSameUnqualifiedType(T, QualType(CurType, 0)))
2566 return NNSLoc.getTypeLoc().getSourceRange();
2570 NNSLoc = NNSLoc.getPrefix();
2573 return SourceRange();
2576 /// Match the given template parameter lists to the given scope
2577 /// specifier, returning the template parameter list that applies to the
2580 /// \param DeclStartLoc the start of the declaration that has a scope
2581 /// specifier or a template parameter list.
2583 /// \param DeclLoc The location of the declaration itself.
2585 /// \param SS the scope specifier that will be matched to the given template
2586 /// parameter lists. This scope specifier precedes a qualified name that is
2589 /// \param TemplateId The template-id following the scope specifier, if there
2590 /// is one. Used to check for a missing 'template<>'.
2592 /// \param ParamLists the template parameter lists, from the outermost to the
2593 /// innermost template parameter lists.
2595 /// \param IsFriend Whether to apply the slightly different rules for
2596 /// matching template parameters to scope specifiers in friend
2599 /// \param IsMemberSpecialization will be set true if the scope specifier
2600 /// denotes a fully-specialized type, and therefore this is a declaration of
2601 /// a member specialization.
2603 /// \returns the template parameter list, if any, that corresponds to the
2604 /// name that is preceded by the scope specifier @p SS. This template
2605 /// parameter list may have template parameters (if we're declaring a
2606 /// template) or may have no template parameters (if we're declaring a
2607 /// template specialization), or may be NULL (if what we're declaring isn't
2608 /// itself a template).
2609 TemplateParameterList *Sema::MatchTemplateParametersToScopeSpecifier(
2610 SourceLocation DeclStartLoc, SourceLocation DeclLoc, const CXXScopeSpec &SS,
2611 TemplateIdAnnotation *TemplateId,
2612 ArrayRef<TemplateParameterList *> ParamLists, bool IsFriend,
2613 bool &IsMemberSpecialization, bool &Invalid) {
2614 IsMemberSpecialization = false;
2617 // The sequence of nested types to which we will match up the template
2618 // parameter lists. We first build this list by starting with the type named
2619 // by the nested-name-specifier and walking out until we run out of types.
2620 SmallVector<QualType, 4> NestedTypes;
2622 if (SS.getScopeRep()) {
2623 if (CXXRecordDecl *Record
2624 = dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, true)))
2625 T = Context.getTypeDeclType(Record);
2627 T = QualType(SS.getScopeRep()->getAsType(), 0);
2630 // If we found an explicit specialization that prevents us from needing
2631 // 'template<>' headers, this will be set to the location of that
2632 // explicit specialization.
2633 SourceLocation ExplicitSpecLoc;
2635 while (!T.isNull()) {
2636 NestedTypes.push_back(T);
2638 // Retrieve the parent of a record type.
2639 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2640 // If this type is an explicit specialization, we're done.
2641 if (ClassTemplateSpecializationDecl *Spec
2642 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2643 if (!isa<ClassTemplatePartialSpecializationDecl>(Spec) &&
2644 Spec->getSpecializationKind() == TSK_ExplicitSpecialization) {
2645 ExplicitSpecLoc = Spec->getLocation();
2648 } else if (Record->getTemplateSpecializationKind()
2649 == TSK_ExplicitSpecialization) {
2650 ExplicitSpecLoc = Record->getLocation();
2654 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Record->getParent()))
2655 T = Context.getTypeDeclType(Parent);
2661 if (const TemplateSpecializationType *TST
2662 = T->getAs<TemplateSpecializationType>()) {
2663 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2664 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Template->getDeclContext()))
2665 T = Context.getTypeDeclType(Parent);
2672 // Look one step prior in a dependent template specialization type.
2673 if (const DependentTemplateSpecializationType *DependentTST
2674 = T->getAs<DependentTemplateSpecializationType>()) {
2675 if (NestedNameSpecifier *NNS = DependentTST->getQualifier())
2676 T = QualType(NNS->getAsType(), 0);
2682 // Look one step prior in a dependent name type.
2683 if (const DependentNameType *DependentName = T->getAs<DependentNameType>()){
2684 if (NestedNameSpecifier *NNS = DependentName->getQualifier())
2685 T = QualType(NNS->getAsType(), 0);
2691 // Retrieve the parent of an enumeration type.
2692 if (const EnumType *EnumT = T->getAs<EnumType>()) {
2693 // FIXME: Forward-declared enums require a TSK_ExplicitSpecialization
2695 EnumDecl *Enum = EnumT->getDecl();
2697 // Get to the parent type.
2698 if (TypeDecl *Parent = dyn_cast<TypeDecl>(Enum->getParent()))
2699 T = Context.getTypeDeclType(Parent);
2707 // Reverse the nested types list, since we want to traverse from the outermost
2708 // to the innermost while checking template-parameter-lists.
2709 std::reverse(NestedTypes.begin(), NestedTypes.end());
2711 // C++0x [temp.expl.spec]p17:
2712 // A member or a member template may be nested within many
2713 // enclosing class templates. In an explicit specialization for
2714 // such a member, the member declaration shall be preceded by a
2715 // template<> for each enclosing class template that is
2716 // explicitly specialized.
2717 bool SawNonEmptyTemplateParameterList = false;
2719 auto CheckExplicitSpecialization = [&](SourceRange Range, bool Recovery) {
2720 if (SawNonEmptyTemplateParameterList) {
2721 Diag(DeclLoc, diag::err_specialize_member_of_template)
2722 << !Recovery << Range;
2724 IsMemberSpecialization = false;
2731 auto DiagnoseMissingExplicitSpecialization = [&] (SourceRange Range) {
2732 // Check that we can have an explicit specialization here.
2733 if (CheckExplicitSpecialization(Range, true))
2736 // We don't have a template header, but we should.
2737 SourceLocation ExpectedTemplateLoc;
2738 if (!ParamLists.empty())
2739 ExpectedTemplateLoc = ParamLists[0]->getTemplateLoc();
2741 ExpectedTemplateLoc = DeclStartLoc;
2743 Diag(DeclLoc, diag::err_template_spec_needs_header)
2745 << FixItHint::CreateInsertion(ExpectedTemplateLoc, "template<> ");
2749 unsigned ParamIdx = 0;
2750 for (unsigned TypeIdx = 0, NumTypes = NestedTypes.size(); TypeIdx != NumTypes;
2752 T = NestedTypes[TypeIdx];
2754 // Whether we expect a 'template<>' header.
2755 bool NeedEmptyTemplateHeader = false;
2757 // Whether we expect a template header with parameters.
2758 bool NeedNonemptyTemplateHeader = false;
2760 // For a dependent type, the set of template parameters that we
2762 TemplateParameterList *ExpectedTemplateParams = nullptr;
2764 // C++0x [temp.expl.spec]p15:
2765 // A member or a member template may be nested within many enclosing
2766 // class templates. In an explicit specialization for such a member, the
2767 // member declaration shall be preceded by a template<> for each
2768 // enclosing class template that is explicitly specialized.
2769 if (CXXRecordDecl *Record = T->getAsCXXRecordDecl()) {
2770 if (ClassTemplatePartialSpecializationDecl *Partial
2771 = dyn_cast<ClassTemplatePartialSpecializationDecl>(Record)) {
2772 ExpectedTemplateParams = Partial->getTemplateParameters();
2773 NeedNonemptyTemplateHeader = true;
2774 } else if (Record->isDependentType()) {
2775 if (Record->getDescribedClassTemplate()) {
2776 ExpectedTemplateParams = Record->getDescribedClassTemplate()
2777 ->getTemplateParameters();
2778 NeedNonemptyTemplateHeader = true;
2780 } else if (ClassTemplateSpecializationDecl *Spec
2781 = dyn_cast<ClassTemplateSpecializationDecl>(Record)) {
2782 // C++0x [temp.expl.spec]p4:
2783 // Members of an explicitly specialized class template are defined
2784 // in the same manner as members of normal classes, and not using
2785 // the template<> syntax.
2786 if (Spec->getSpecializationKind() != TSK_ExplicitSpecialization)
2787 NeedEmptyTemplateHeader = true;
2790 } else if (Record->getTemplateSpecializationKind()) {
2791 if (Record->getTemplateSpecializationKind()
2792 != TSK_ExplicitSpecialization &&
2793 TypeIdx == NumTypes - 1)
2794 IsMemberSpecialization = true;
2798 } else if (const TemplateSpecializationType *TST
2799 = T->getAs<TemplateSpecializationType>()) {
2800 if (TemplateDecl *Template = TST->getTemplateName().getAsTemplateDecl()) {
2801 ExpectedTemplateParams = Template->getTemplateParameters();
2802 NeedNonemptyTemplateHeader = true;
2804 } else if (T->getAs<DependentTemplateSpecializationType>()) {
2805 // FIXME: We actually could/should check the template arguments here
2806 // against the corresponding template parameter list.
2807 NeedNonemptyTemplateHeader = false;
2810 // C++ [temp.expl.spec]p16:
2811 // In an explicit specialization declaration for a member of a class
2812 // template or a member template that ap- pears in namespace scope, the
2813 // member template and some of its enclosing class templates may remain
2814 // unspecialized, except that the declaration shall not explicitly
2815 // specialize a class member template if its en- closing class templates
2816 // are not explicitly specialized as well.
2817 if (ParamIdx < ParamLists.size()) {
2818 if (ParamLists[ParamIdx]->size() == 0) {
2819 if (CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2823 SawNonEmptyTemplateParameterList = true;
2826 if (NeedEmptyTemplateHeader) {
2827 // If we're on the last of the types, and we need a 'template<>' header
2828 // here, then it's a member specialization.
2829 if (TypeIdx == NumTypes - 1)
2830 IsMemberSpecialization = true;
2832 if (ParamIdx < ParamLists.size()) {
2833 if (ParamLists[ParamIdx]->size() > 0) {
2834 // The header has template parameters when it shouldn't. Complain.
2835 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2836 diag::err_template_param_list_matches_nontemplate)
2838 << SourceRange(ParamLists[ParamIdx]->getLAngleLoc(),
2839 ParamLists[ParamIdx]->getRAngleLoc())
2840 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2845 // Consume this template header.
2851 if (DiagnoseMissingExplicitSpecialization(
2852 getRangeOfTypeInNestedNameSpecifier(Context, T, SS)))
2858 if (NeedNonemptyTemplateHeader) {
2859 // In friend declarations we can have template-ids which don't
2860 // depend on the corresponding template parameter lists. But
2861 // assume that empty parameter lists are supposed to match this
2863 if (IsFriend && T->isDependentType()) {
2864 if (ParamIdx < ParamLists.size() &&
2865 DependsOnTemplateParameters(T, ParamLists[ParamIdx]))
2866 ExpectedTemplateParams = nullptr;
2871 if (ParamIdx < ParamLists.size()) {
2872 // Check the template parameter list, if we can.
2873 if (ExpectedTemplateParams &&
2874 !TemplateParameterListsAreEqual(ParamLists[ParamIdx],
2875 ExpectedTemplateParams,
2876 true, TPL_TemplateMatch))
2880 CheckTemplateParameterList(ParamLists[ParamIdx], nullptr,
2881 TPC_ClassTemplateMember))
2888 Diag(DeclLoc, diag::err_template_spec_needs_template_parameters)
2890 << getRangeOfTypeInNestedNameSpecifier(Context, T, SS);
2896 // If there were at least as many template-ids as there were template
2897 // parameter lists, then there are no template parameter lists remaining for
2898 // the declaration itself.
2899 if (ParamIdx >= ParamLists.size()) {
2900 if (TemplateId && !IsFriend) {
2901 // We don't have a template header for the declaration itself, but we
2903 DiagnoseMissingExplicitSpecialization(SourceRange(TemplateId->LAngleLoc,
2904 TemplateId->RAngleLoc));
2906 // Fabricate an empty template parameter list for the invented header.
2907 return TemplateParameterList::Create(Context, SourceLocation(),
2908 SourceLocation(), None,
2909 SourceLocation(), nullptr);
2915 // If there were too many template parameter lists, complain about that now.
2916 if (ParamIdx < ParamLists.size() - 1) {
2917 bool HasAnyExplicitSpecHeader = false;
2918 bool AllExplicitSpecHeaders = true;
2919 for (unsigned I = ParamIdx, E = ParamLists.size() - 1; I != E; ++I) {
2920 if (ParamLists[I]->size() == 0)
2921 HasAnyExplicitSpecHeader = true;
2923 AllExplicitSpecHeaders = false;
2926 Diag(ParamLists[ParamIdx]->getTemplateLoc(),
2927 AllExplicitSpecHeaders ? diag::warn_template_spec_extra_headers
2928 : diag::err_template_spec_extra_headers)
2929 << SourceRange(ParamLists[ParamIdx]->getTemplateLoc(),
2930 ParamLists[ParamLists.size() - 2]->getRAngleLoc());
2932 // If there was a specialization somewhere, such that 'template<>' is
2933 // not required, and there were any 'template<>' headers, note where the
2934 // specialization occurred.
2935 if (ExplicitSpecLoc.isValid() && HasAnyExplicitSpecHeader)
2936 Diag(ExplicitSpecLoc,
2937 diag::note_explicit_template_spec_does_not_need_header)
2938 << NestedTypes.back();
2940 // We have a template parameter list with no corresponding scope, which
2941 // means that the resulting template declaration can't be instantiated
2942 // properly (we'll end up with dependent nodes when we shouldn't).
2943 if (!AllExplicitSpecHeaders)
2947 // C++ [temp.expl.spec]p16:
2948 // In an explicit specialization declaration for a member of a class
2949 // template or a member template that ap- pears in namespace scope, the
2950 // member template and some of its enclosing class templates may remain
2951 // unspecialized, except that the declaration shall not explicitly
2952 // specialize a class member template if its en- closing class templates
2953 // are not explicitly specialized as well.
2954 if (ParamLists.back()->size() == 0 &&
2955 CheckExplicitSpecialization(ParamLists[ParamIdx]->getSourceRange(),
2959 // Return the last template parameter list, which corresponds to the
2960 // entity being declared.
2961 return ParamLists.back();
2964 void Sema::NoteAllFoundTemplates(TemplateName Name) {
2965 if (TemplateDecl *Template = Name.getAsTemplateDecl()) {
2966 Diag(Template->getLocation(), diag::note_template_declared_here)
2967 << (isa<FunctionTemplateDecl>(Template)
2969 : isa<ClassTemplateDecl>(Template)
2971 : isa<VarTemplateDecl>(Template)
2973 : isa<TypeAliasTemplateDecl>(Template) ? 3 : 4)
2974 << Template->getDeclName();
2978 if (OverloadedTemplateStorage *OST = Name.getAsOverloadedTemplate()) {
2979 for (OverloadedTemplateStorage::iterator I = OST->begin(),
2982 Diag((*I)->getLocation(), diag::note_template_declared_here)
2983 << 0 << (*I)->getDeclName();
2990 checkBuiltinTemplateIdType(Sema &SemaRef, BuiltinTemplateDecl *BTD,
2991 const SmallVectorImpl<TemplateArgument> &Converted,
2992 SourceLocation TemplateLoc,
2993 TemplateArgumentListInfo &TemplateArgs) {
2994 ASTContext &Context = SemaRef.getASTContext();
2995 switch (BTD->getBuiltinTemplateKind()) {
2996 case BTK__make_integer_seq: {
2997 // Specializations of __make_integer_seq<S, T, N> are treated like
2998 // S<T, 0, ..., N-1>.
3000 // C++14 [inteseq.intseq]p1:
3001 // T shall be an integer type.
3002 if (!Converted[1].getAsType()->isIntegralType(Context)) {
3003 SemaRef.Diag(TemplateArgs[1].getLocation(),
3004 diag::err_integer_sequence_integral_element_type);
3008 // C++14 [inteseq.make]p1:
3009 // If N is negative the program is ill-formed.
3010 TemplateArgument NumArgsArg = Converted[2];
3011 llvm::APSInt NumArgs = NumArgsArg.getAsIntegral();
3013 SemaRef.Diag(TemplateArgs[2].getLocation(),
3014 diag::err_integer_sequence_negative_length);
3018 QualType ArgTy = NumArgsArg.getIntegralType();
3019 TemplateArgumentListInfo SyntheticTemplateArgs;
3020 // The type argument gets reused as the first template argument in the
3021 // synthetic template argument list.
3022 SyntheticTemplateArgs.addArgument(TemplateArgs[1]);
3023 // Expand N into 0 ... N-1.
3024 for (llvm::APSInt I(NumArgs.getBitWidth(), NumArgs.isUnsigned());
3026 TemplateArgument TA(Context, I, ArgTy);
3027 SyntheticTemplateArgs.addArgument(SemaRef.getTrivialTemplateArgumentLoc(
3028 TA, ArgTy, TemplateArgs[2].getLocation()));
3030 // The first template argument will be reused as the template decl that
3031 // our synthetic template arguments will be applied to.
3032 return SemaRef.CheckTemplateIdType(Converted[0].getAsTemplate(),
3033 TemplateLoc, SyntheticTemplateArgs);
3036 case BTK__type_pack_element:
3037 // Specializations of
3038 // __type_pack_element<Index, T_1, ..., T_N>
3039 // are treated like T_Index.
3040 assert(Converted.size() == 2 &&
3041 "__type_pack_element should be given an index and a parameter pack");
3043 // If the Index is out of bounds, the program is ill-formed.
3044 TemplateArgument IndexArg = Converted[0], Ts = Converted[1];
3045 llvm::APSInt Index = IndexArg.getAsIntegral();
3046 assert(Index >= 0 && "the index used with __type_pack_element should be of "
3047 "type std::size_t, and hence be non-negative");
3048 if (Index >= Ts.pack_size()) {
3049 SemaRef.Diag(TemplateArgs[0].getLocation(),
3050 diag::err_type_pack_element_out_of_bounds);
3054 // We simply return the type at index `Index`.
3055 auto Nth = std::next(Ts.pack_begin(), Index.getExtValue());
3056 return Nth->getAsType();
3058 llvm_unreachable("unexpected BuiltinTemplateDecl!");
3061 /// Determine whether this alias template is "enable_if_t".
3062 static bool isEnableIfAliasTemplate(TypeAliasTemplateDecl *AliasTemplate) {
3063 return AliasTemplate->getName().equals("enable_if_t");
3066 /// Collect all of the separable terms in the given condition, which
3067 /// might be a conjunction.
3069 /// FIXME: The right answer is to convert the logical expression into
3070 /// disjunctive normal form, so we can find the first failed term
3071 /// within each possible clause.
3072 static void collectConjunctionTerms(Expr *Clause,
3073 SmallVectorImpl<Expr *> &Terms) {
3074 if (auto BinOp = dyn_cast<BinaryOperator>(Clause->IgnoreParenImpCasts())) {
3075 if (BinOp->getOpcode() == BO_LAnd) {
3076 collectConjunctionTerms(BinOp->getLHS(), Terms);
3077 collectConjunctionTerms(BinOp->getRHS(), Terms);
3083 Terms.push_back(Clause);
3086 // The ranges-v3 library uses an odd pattern of a top-level "||" with
3087 // a left-hand side that is value-dependent but never true. Identify
3088 // the idiom and ignore that term.
3089 static Expr *lookThroughRangesV3Condition(Preprocessor &PP, Expr *Cond) {
3091 auto *BinOp = dyn_cast<BinaryOperator>(Cond->IgnoreParenImpCasts());
3092 if (!BinOp) return Cond;
3094 if (BinOp->getOpcode() != BO_LOr) return Cond;
3096 // With an inner '==' that has a literal on the right-hand side.
3097 Expr *LHS = BinOp->getLHS();
3098 auto *InnerBinOp = dyn_cast<BinaryOperator>(LHS->IgnoreParenImpCasts());
3099 if (!InnerBinOp) return Cond;
3101 if (InnerBinOp->getOpcode() != BO_EQ ||
3102 !isa<IntegerLiteral>(InnerBinOp->getRHS()))
3105 // If the inner binary operation came from a macro expansion named
3106 // CONCEPT_REQUIRES or CONCEPT_REQUIRES_, return the right-hand side
3107 // of the '||', which is the real, user-provided condition.
3108 SourceLocation Loc = InnerBinOp->getExprLoc();
3109 if (!Loc.isMacroID()) return Cond;
3111 StringRef MacroName = PP.getImmediateMacroName(Loc);
3112 if (MacroName == "CONCEPT_REQUIRES" || MacroName == "CONCEPT_REQUIRES_")
3113 return BinOp->getRHS();
3120 // A PrinterHelper that prints more helpful diagnostics for some sub-expressions
3121 // within failing boolean expression, such as substituting template parameters
3122 // for actual types.
3123 class FailedBooleanConditionPrinterHelper : public PrinterHelper {
3125 explicit FailedBooleanConditionPrinterHelper(const PrintingPolicy &P)
3128 bool handledStmt(Stmt *E, raw_ostream &OS) override {
3129 const auto *DR = dyn_cast<DeclRefExpr>(E);
3130 if (DR && DR->getQualifier()) {
3131 // If this is a qualified name, expand the template arguments in nested
3133 DR->getQualifier()->print(OS, Policy, true);
3134 // Then print the decl itself.
3135 const ValueDecl *VD = DR->getDecl();
3136 OS << VD->getName();
3137 if (const auto *IV = dyn_cast<VarTemplateSpecializationDecl>(VD)) {
3138 // This is a template variable, print the expanded template arguments.
3139 printTemplateArgumentList(OS, IV->getTemplateArgs().asArray(), Policy);
3147 const PrintingPolicy Policy;
3150 } // end anonymous namespace
3152 std::pair<Expr *, std::string>
3153 Sema::findFailedBooleanCondition(Expr *Cond) {
3154 Cond = lookThroughRangesV3Condition(PP, Cond);
3156 // Separate out all of the terms in a conjunction.
3157 SmallVector<Expr *, 4> Terms;
3158 collectConjunctionTerms(Cond, Terms);
3160 // Determine which term failed.
3161 Expr *FailedCond = nullptr;
3162 for (Expr *Term : Terms) {
3163 Expr *TermAsWritten = Term->IgnoreParenImpCasts();
3165 // Literals are uninteresting.
3166 if (isa<CXXBoolLiteralExpr>(TermAsWritten) ||
3167 isa<IntegerLiteral>(TermAsWritten))
3170 // The initialization of the parameter from the argument is
3171 // a constant-evaluated context.
3172 EnterExpressionEvaluationContext ConstantEvaluated(
3173 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
3176 if (Term->EvaluateAsBooleanCondition(Succeeded, Context) &&
3178 FailedCond = TermAsWritten;
3183 FailedCond = Cond->IgnoreParenImpCasts();
3185 std::string Description;
3187 llvm::raw_string_ostream Out(Description);
3188 PrintingPolicy Policy = getPrintingPolicy();
3189 Policy.PrintCanonicalTypes = true;
3190 FailedBooleanConditionPrinterHelper Helper(Policy);
3191 FailedCond->printPretty(Out, &Helper, Policy, 0, "\n", nullptr);
3193 return { FailedCond, Description };
3196 QualType Sema::CheckTemplateIdType(TemplateName Name,
3197 SourceLocation TemplateLoc,
3198 TemplateArgumentListInfo &TemplateArgs) {
3199 DependentTemplateName *DTN
3200 = Name.getUnderlying().getAsDependentTemplateName();
3201 if (DTN && DTN->isIdentifier())
3202 // When building a template-id where the template-name is dependent,
3203 // assume the template is a type template. Either our assumption is
3204 // correct, or the code is ill-formed and will be diagnosed when the
3205 // dependent name is substituted.
3206 return Context.getDependentTemplateSpecializationType(ETK_None,
3207 DTN->getQualifier(),
3208 DTN->getIdentifier(),
3211 TemplateDecl *Template = Name.getAsTemplateDecl();
3212 if (!Template || isa<FunctionTemplateDecl>(Template) ||
3213 isa<VarTemplateDecl>(Template) ||
3214 isa<ConceptDecl>(Template)) {
3215 // We might have a substituted template template parameter pack. If so,
3216 // build a template specialization type for it.
3217 if (Name.getAsSubstTemplateTemplateParmPack())
3218 return Context.getTemplateSpecializationType(Name, TemplateArgs);
3220 Diag(TemplateLoc, diag::err_template_id_not_a_type)
3222 NoteAllFoundTemplates(Name);
3226 // Check that the template argument list is well-formed for this
3228 SmallVector<TemplateArgument, 4> Converted;
3229 if (CheckTemplateArgumentList(Template, TemplateLoc, TemplateArgs,
3235 bool InstantiationDependent = false;
3236 if (TypeAliasTemplateDecl *AliasTemplate =
3237 dyn_cast<TypeAliasTemplateDecl>(Template)) {
3238 // Find the canonical type for this type alias template specialization.
3239 TypeAliasDecl *Pattern = AliasTemplate->getTemplatedDecl();
3240 if (Pattern->isInvalidDecl())
3243 TemplateArgumentList StackTemplateArgs(TemplateArgumentList::OnStack,
3246 // Only substitute for the innermost template argument list.
3247 MultiLevelTemplateArgumentList TemplateArgLists;
3248 TemplateArgLists.addOuterTemplateArguments(&StackTemplateArgs);
3249 unsigned Depth = AliasTemplate->getTemplateParameters()->getDepth();
3250 for (unsigned I = 0; I < Depth; ++I)
3251 TemplateArgLists.addOuterTemplateArguments(None);
3253 LocalInstantiationScope Scope(*this);
3254 InstantiatingTemplate Inst(*this, TemplateLoc, Template);
3255 if (Inst.isInvalid())
3258 CanonType = SubstType(Pattern->getUnderlyingType(),
3259 TemplateArgLists, AliasTemplate->getLocation(),
3260 AliasTemplate->getDeclName());
3261 if (CanonType.isNull()) {
3262 // If this was enable_if and we failed to find the nested type
3263 // within enable_if in a SFINAE context, dig out the specific
3264 // enable_if condition that failed and present that instead.
3265 if (isEnableIfAliasTemplate(AliasTemplate)) {
3266 if (auto DeductionInfo = isSFINAEContext()) {
3267 if (*DeductionInfo &&
3268 (*DeductionInfo)->hasSFINAEDiagnostic() &&
3269 (*DeductionInfo)->peekSFINAEDiagnostic().second.getDiagID() ==
3270 diag::err_typename_nested_not_found_enable_if &&
3271 TemplateArgs[0].getArgument().getKind()
3272 == TemplateArgument::Expression) {
3274 std::string FailedDescription;
3275 std::tie(FailedCond, FailedDescription) =
3276 findFailedBooleanCondition(TemplateArgs[0].getSourceExpression());
3278 // Remove the old SFINAE diagnostic.
3279 PartialDiagnosticAt OldDiag =
3280 {SourceLocation(), PartialDiagnostic::NullDiagnostic()};
3281 (*DeductionInfo)->takeSFINAEDiagnostic(OldDiag);
3283 // Add a new SFINAE diagnostic specifying which condition
3285 (*DeductionInfo)->addSFINAEDiagnostic(
3287 PDiag(diag::err_typename_nested_not_found_requirement)
3288 << FailedDescription
3289 << FailedCond->getSourceRange());
3296 } else if (Name.isDependent() ||
3297 TemplateSpecializationType::anyDependentTemplateArguments(
3298 TemplateArgs, InstantiationDependent)) {
3299 // This class template specialization is a dependent
3300 // type. Therefore, its canonical type is another class template
3301 // specialization type that contains all of the converted
3302 // arguments in canonical form. This ensures that, e.g., A<T> and
3303 // A<T, T> have identical types when A is declared as:
3305 // template<typename T, typename U = T> struct A;
3306 CanonType = Context.getCanonicalTemplateSpecializationType(Name, Converted);
3308 // This might work out to be a current instantiation, in which
3309 // case the canonical type needs to be the InjectedClassNameType.
3311 // TODO: in theory this could be a simple hashtable lookup; most
3312 // changes to CurContext don't change the set of current
3314 if (isa<ClassTemplateDecl>(Template)) {
3315 for (DeclContext *Ctx = CurContext; Ctx; Ctx = Ctx->getLookupParent()) {
3316 // If we get out to a namespace, we're done.
3317 if (Ctx->isFileContext()) break;
3319 // If this isn't a record, keep looking.
3320 CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(Ctx);
3321 if (!Record) continue;
3323 // Look for one of the two cases with InjectedClassNameTypes
3324 // and check whether it's the same template.
3325 if (!isa<ClassTemplatePartialSpecializationDecl>(Record) &&
3326 !Record->getDescribedClassTemplate())
3329 // Fetch the injected class name type and check whether its
3330 // injected type is equal to the type we just built.
3331 QualType ICNT = Context.getTypeDeclType(Record);
3332 QualType Injected = cast<InjectedClassNameType>(ICNT)
3333 ->getInjectedSpecializationType();
3335 if (CanonType != Injected->getCanonicalTypeInternal())
3338 // If so, the canonical type of this TST is the injected
3339 // class name type of the record we just found.
3340 assert(ICNT.isCanonical());
3345 } else if (ClassTemplateDecl *ClassTemplate
3346 = dyn_cast<ClassTemplateDecl>(Template)) {
3347 // Find the class template specialization declaration that
3348 // corresponds to these arguments.
3349 void *InsertPos = nullptr;
3350 ClassTemplateSpecializationDecl *Decl
3351 = ClassTemplate->findSpecialization(Converted, InsertPos);
3353 // This is the first time we have referenced this class template
3354 // specialization. Create the canonical declaration and add it to
3355 // the set of specializations.
3356 Decl = ClassTemplateSpecializationDecl::Create(
3357 Context, ClassTemplate->getTemplatedDecl()->getTagKind(),
3358 ClassTemplate->getDeclContext(),
3359 ClassTemplate->getTemplatedDecl()->getBeginLoc(),
3360 ClassTemplate->getLocation(), ClassTemplate, Converted, nullptr);
3361 ClassTemplate->AddSpecialization(Decl, InsertPos);
3362 if (ClassTemplate->isOutOfLine())
3363 Decl->setLexicalDeclContext(ClassTemplate->getLexicalDeclContext());
3366 if (Decl->getSpecializationKind() == TSK_Undeclared) {
3367 MultiLevelTemplateArgumentList TemplateArgLists;
3368 TemplateArgLists.addOuterTemplateArguments(Converted);
3369 InstantiateAttrsForDecl(TemplateArgLists, ClassTemplate->getTemplatedDecl(),
3373 // Diagnose uses of this specialization.
3374 (void)DiagnoseUseOfDecl(Decl, TemplateLoc);
3376 CanonType = Context.getTypeDeclType(Decl);
3377 assert(isa<RecordType>(CanonType) &&
3378 "type of non-dependent specialization is not a RecordType");
3379 } else if (auto *BTD = dyn_cast<BuiltinTemplateDecl>(Template)) {
3380 CanonType = checkBuiltinTemplateIdType(*this, BTD, Converted, TemplateLoc,
3384 // Build the fully-sugared type for this class template
3385 // specialization, which refers back to the class template
3386 // specialization we created or found.
3387 return Context.getTemplateSpecializationType(Name, TemplateArgs, CanonType);
3390 void Sema::ActOnUndeclaredTypeTemplateName(Scope *S, TemplateTy &ParsedName,
3391 TemplateNameKind &TNK,
3392 SourceLocation NameLoc,
3393 IdentifierInfo *&II) {
3394 assert(TNK == TNK_Undeclared_template && "not an undeclared template name");
3396 TemplateName Name = ParsedName.get();
3397 auto *ATN = Name.getAsAssumedTemplateName();
3398 assert(ATN && "not an assumed template name");
3399 II = ATN->getDeclName().getAsIdentifierInfo();
3401 if (!resolveAssumedTemplateNameAsType(S, Name, NameLoc, /*Diagnose*/false)) {
3402 // Resolved to a type template name.
3403 ParsedName = TemplateTy::make(Name);
3404 TNK = TNK_Type_template;
3408 bool Sema::resolveAssumedTemplateNameAsType(Scope *S, TemplateName &Name,
3409 SourceLocation NameLoc,
3411 // We assumed this undeclared identifier to be an (ADL-only) function
3412 // template name, but it was used in a context where a type was required.
3413 // Try to typo-correct it now.
3414 AssumedTemplateStorage *ATN = Name.getAsAssumedTemplateName();
3415 assert(ATN && "not an assumed template name");
3417 LookupResult R(*this, ATN->getDeclName(), NameLoc, LookupOrdinaryName);
3418 struct CandidateCallback : CorrectionCandidateCallback {
3419 bool ValidateCandidate(const TypoCorrection &TC) override {
3420 return TC.getCorrectionDecl() &&
3421 getAsTypeTemplateDecl(TC.getCorrectionDecl());
3423 std::unique_ptr<CorrectionCandidateCallback> clone() override {
3424 return std::make_unique<CandidateCallback>(*this);
3428 TypoCorrection Corrected =
3429 CorrectTypo(R.getLookupNameInfo(), R.getLookupKind(), S, nullptr,
3430 FilterCCC, CTK_ErrorRecovery);
3431 if (Corrected && Corrected.getFoundDecl()) {
3432 diagnoseTypo(Corrected, PDiag(diag::err_no_template_suggest)
3433 << ATN->getDeclName());
3434 Name = TemplateName(Corrected.getCorrectionDeclAs<TemplateDecl>());
3439 Diag(R.getNameLoc(), diag::err_no_template) << R.getLookupName();
3443 TypeResult Sema::ActOnTemplateIdType(
3444 Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc,
3445 TemplateTy TemplateD, IdentifierInfo *TemplateII,
3446 SourceLocation TemplateIILoc, SourceLocation LAngleLoc,
3447 ASTTemplateArgsPtr TemplateArgsIn, SourceLocation RAngleLoc,
3448 bool IsCtorOrDtorName, bool IsClassName) {
3452 if (!IsCtorOrDtorName && !IsClassName && SS.isSet()) {
3453 DeclContext *LookupCtx = computeDeclContext(SS, /*EnteringContext*/false);
3455 // C++ [temp.res]p3:
3456 // A qualified-id that refers to a type and in which the
3457 // nested-name-specifier depends on a template-parameter (14.6.2)
3458 // shall be prefixed by the keyword typename to indicate that the
3459 // qualified-id denotes a type, forming an
3460 // elaborated-type-specifier (7.1.5.3).
3461 if (!LookupCtx && isDependentScopeSpecifier(SS)) {
3462 Diag(SS.getBeginLoc(), diag::err_typename_missing_template)
3463 << SS.getScopeRep() << TemplateII->getName();
3464 // Recover as if 'typename' were specified.
3465 // FIXME: This is not quite correct recovery as we don't transform SS
3466 // into the corresponding dependent form (and we don't diagnose missing
3467 // 'template' keywords within SS as a result).
3468 return ActOnTypenameType(nullptr, SourceLocation(), SS, TemplateKWLoc,
3469 TemplateD, TemplateII, TemplateIILoc, LAngleLoc,
3470 TemplateArgsIn, RAngleLoc);
3473 // Per C++ [class.qual]p2, if the template-id was an injected-class-name,
3474 // it's not actually allowed to be used as a type in most cases. Because
3475 // we annotate it before we know whether it's valid, we have to check for
3477 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(LookupCtx);
3478 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
3480 TemplateKWLoc.isInvalid()
3481 ? diag::err_out_of_line_qualified_id_type_names_constructor
3482 : diag::ext_out_of_line_qualified_id_type_names_constructor)
3483 << TemplateII << 0 /*injected-class-name used as template name*/
3484 << 1 /*if any keyword was present, it was 'template'*/;
3488 TemplateName Template = TemplateD.get();
3489 if (Template.getAsAssumedTemplateName() &&
3490 resolveAssumedTemplateNameAsType(S, Template, TemplateIILoc))
3493 // Translate the parser's template argument list in our AST format.
3494 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3495 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3497 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3499 = Context.getDependentTemplateSpecializationType(ETK_None,
3500 DTN->getQualifier(),
3501 DTN->getIdentifier(),
3503 // Build type-source information.
3505 DependentTemplateSpecializationTypeLoc SpecTL
3506 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3507 SpecTL.setElaboratedKeywordLoc(SourceLocation());
3508 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3509 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3510 SpecTL.setTemplateNameLoc(TemplateIILoc);
3511 SpecTL.setLAngleLoc(LAngleLoc);
3512 SpecTL.setRAngleLoc(RAngleLoc);
3513 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3514 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3515 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3518 QualType Result = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
3519 if (Result.isNull())
3522 // Build type-source information.
3524 TemplateSpecializationTypeLoc SpecTL
3525 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3526 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3527 SpecTL.setTemplateNameLoc(TemplateIILoc);
3528 SpecTL.setLAngleLoc(LAngleLoc);
3529 SpecTL.setRAngleLoc(RAngleLoc);
3530 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3531 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3533 // NOTE: avoid constructing an ElaboratedTypeLoc if this is a
3534 // constructor or destructor name (in such a case, the scope specifier
3535 // will be attached to the enclosing Decl or Expr node).
3536 if (SS.isNotEmpty() && !IsCtorOrDtorName) {
3537 // Create an elaborated-type-specifier containing the nested-name-specifier.
3538 Result = Context.getElaboratedType(ETK_None, SS.getScopeRep(), Result);
3539 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3540 ElabTL.setElaboratedKeywordLoc(SourceLocation());
3541 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3544 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3547 TypeResult Sema::ActOnTagTemplateIdType(TagUseKind TUK,
3548 TypeSpecifierType TagSpec,
3549 SourceLocation TagLoc,
3551 SourceLocation TemplateKWLoc,
3552 TemplateTy TemplateD,
3553 SourceLocation TemplateLoc,
3554 SourceLocation LAngleLoc,
3555 ASTTemplateArgsPtr TemplateArgsIn,
3556 SourceLocation RAngleLoc) {
3557 TemplateName Template = TemplateD.get();
3559 // Translate the parser's template argument list in our AST format.
3560 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
3561 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
3563 // Determine the tag kind
3564 TagTypeKind TagKind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
3565 ElaboratedTypeKeyword Keyword
3566 = TypeWithKeyword::getKeywordForTagTypeKind(TagKind);
3568 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
3569 QualType T = Context.getDependentTemplateSpecializationType(Keyword,
3570 DTN->getQualifier(),
3571 DTN->getIdentifier(),
3574 // Build type-source information.
3576 DependentTemplateSpecializationTypeLoc SpecTL
3577 = TLB.push<DependentTemplateSpecializationTypeLoc>(T);
3578 SpecTL.setElaboratedKeywordLoc(TagLoc);
3579 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
3580 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3581 SpecTL.setTemplateNameLoc(TemplateLoc);
3582 SpecTL.setLAngleLoc(LAngleLoc);
3583 SpecTL.setRAngleLoc(RAngleLoc);
3584 for (unsigned I = 0, N = SpecTL.getNumArgs(); I != N; ++I)
3585 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
3586 return CreateParsedType(T, TLB.getTypeSourceInfo(Context, T));
3589 if (TypeAliasTemplateDecl *TAT =
3590 dyn_cast_or_null<TypeAliasTemplateDecl>(Template.getAsTemplateDecl())) {
3591 // C++0x [dcl.type.elab]p2:
3592 // If the identifier resolves to a typedef-name or the simple-template-id
3593 // resolves to an alias template specialization, the
3594 // elaborated-type-specifier is ill-formed.
3595 Diag(TemplateLoc, diag::err_tag_reference_non_tag)
3596 << TAT << NTK_TypeAliasTemplate << TagKind;
3597 Diag(TAT->getLocation(), diag::note_declared_at);
3600 QualType Result = CheckTemplateIdType(Template, TemplateLoc, TemplateArgs);
3601 if (Result.isNull())
3602 return TypeResult(true);
3604 // Check the tag kind
3605 if (const RecordType *RT = Result->getAs<RecordType>()) {
3606 RecordDecl *D = RT->getDecl();
3608 IdentifierInfo *Id = D->getIdentifier();
3609 assert(Id && "templated class must have an identifier");
3611 if (!isAcceptableTagRedeclaration(D, TagKind, TUK == TUK_Definition,
3613 Diag(TagLoc, diag::err_use_with_wrong_tag)
3615 << FixItHint::CreateReplacement(SourceRange(TagLoc), D->getKindName());
3616 Diag(D->getLocation(), diag::note_previous_use);
3620 // Provide source-location information for the template specialization.
3622 TemplateSpecializationTypeLoc SpecTL
3623 = TLB.push<TemplateSpecializationTypeLoc>(Result);
3624 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
3625 SpecTL.setTemplateNameLoc(TemplateLoc);
3626 SpecTL.setLAngleLoc(LAngleLoc);
3627 SpecTL.setRAngleLoc(RAngleLoc);
3628 for (unsigned i = 0, e = SpecTL.getNumArgs(); i != e; ++i)
3629 SpecTL.setArgLocInfo(i, TemplateArgs[i].getLocInfo());
3631 // Construct an elaborated type containing the nested-name-specifier (if any)
3633 Result = Context.getElaboratedType(Keyword, SS.getScopeRep(), Result);
3634 ElaboratedTypeLoc ElabTL = TLB.push<ElaboratedTypeLoc>(Result);
3635 ElabTL.setElaboratedKeywordLoc(TagLoc);
3636 ElabTL.setQualifierLoc(SS.getWithLocInContext(Context));
3637 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
3640 static bool CheckTemplateSpecializationScope(Sema &S, NamedDecl *Specialized,
3641 NamedDecl *PrevDecl,
3643 bool IsPartialSpecialization);
3645 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D);
3647 static bool isTemplateArgumentTemplateParameter(
3648 const TemplateArgument &Arg, unsigned Depth, unsigned Index) {
3649 switch (Arg.getKind()) {
3650 case TemplateArgument::Null:
3651 case TemplateArgument::NullPtr:
3652 case TemplateArgument::Integral:
3653 case TemplateArgument::Declaration:
3654 case TemplateArgument::Pack:
3655 case TemplateArgument::TemplateExpansion:
3658 case TemplateArgument::Type: {
3659 QualType Type = Arg.getAsType();
3660 const TemplateTypeParmType *TPT =
3661 Arg.getAsType()->getAs<TemplateTypeParmType>();
3662 return TPT && !Type.hasQualifiers() &&
3663 TPT->getDepth() == Depth && TPT->getIndex() == Index;
3666 case TemplateArgument::Expression: {
3667 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg.getAsExpr());
3668 if (!DRE || !DRE->getDecl())
3670 const NonTypeTemplateParmDecl *NTTP =
3671 dyn_cast<NonTypeTemplateParmDecl>(DRE->getDecl());
3672 return NTTP && NTTP->getDepth() == Depth && NTTP->getIndex() == Index;
3675 case TemplateArgument::Template:
3676 const TemplateTemplateParmDecl *TTP =
3677 dyn_cast_or_null<TemplateTemplateParmDecl>(
3678 Arg.getAsTemplateOrTemplatePattern().getAsTemplateDecl());
3679 return TTP && TTP->getDepth() == Depth && TTP->getIndex() == Index;
3681 llvm_unreachable("unexpected kind of template argument");
3684 static bool isSameAsPrimaryTemplate(TemplateParameterList *Params,
3685 ArrayRef<TemplateArgument> Args) {
3686 if (Params->size() != Args.size())
3689 unsigned Depth = Params->getDepth();
3691 for (unsigned I = 0, N = Args.size(); I != N; ++I) {
3692 TemplateArgument Arg = Args[I];
3694 // If the parameter is a pack expansion, the argument must be a pack
3695 // whose only element is a pack expansion.
3696 if (Params->getParam(I)->isParameterPack()) {
3697 if (Arg.getKind() != TemplateArgument::Pack || Arg.pack_size() != 1 ||
3698 !Arg.pack_begin()->isPackExpansion())
3700 Arg = Arg.pack_begin()->getPackExpansionPattern();
3703 if (!isTemplateArgumentTemplateParameter(Arg, Depth, I))
3710 /// Convert the parser's template argument list representation into our form.
3711 static TemplateArgumentListInfo
3712 makeTemplateArgumentListInfo(Sema &S, TemplateIdAnnotation &TemplateId) {
3713 TemplateArgumentListInfo TemplateArgs(TemplateId.LAngleLoc,
3714 TemplateId.RAngleLoc);
3715 ASTTemplateArgsPtr TemplateArgsPtr(TemplateId.getTemplateArgs(),
3716 TemplateId.NumArgs);
3717 S.translateTemplateArguments(TemplateArgsPtr, TemplateArgs);
3718 return TemplateArgs;
3721 template<typename PartialSpecDecl>
3722 static void checkMoreSpecializedThanPrimary(Sema &S, PartialSpecDecl *Partial) {
3723 if (Partial->getDeclContext()->isDependentContext())
3726 // FIXME: Get the TDK from deduction in order to provide better diagnostics
3727 // for non-substitution-failure issues?
3728 TemplateDeductionInfo Info(Partial->getLocation());
3729 if (S.isMoreSpecializedThanPrimary(Partial, Info))
3732 auto *Template = Partial->getSpecializedTemplate();
3733 S.Diag(Partial->getLocation(),
3734 diag::ext_partial_spec_not_more_specialized_than_primary)
3735 << isa<VarTemplateDecl>(Template);
3737 if (Info.hasSFINAEDiagnostic()) {
3738 PartialDiagnosticAt Diag = {SourceLocation(),
3739 PartialDiagnostic::NullDiagnostic()};
3740 Info.takeSFINAEDiagnostic(Diag);
3741 SmallString<128> SFINAEArgString;
3742 Diag.second.EmitToString(S.getDiagnostics(), SFINAEArgString);
3744 diag::note_partial_spec_not_more_specialized_than_primary)
3748 S.Diag(Template->getLocation(), diag::note_template_decl_here);
3752 noteNonDeducibleParameters(Sema &S, TemplateParameterList *TemplateParams,
3753 const llvm::SmallBitVector &DeducibleParams) {
3754 for (unsigned I = 0, N = DeducibleParams.size(); I != N; ++I) {
3755 if (!DeducibleParams[I]) {
3756 NamedDecl *Param = TemplateParams->getParam(I);
3757 if (Param->getDeclName())
3758 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3759 << Param->getDeclName();
3761 S.Diag(Param->getLocation(), diag::note_non_deducible_parameter)
3768 template<typename PartialSpecDecl>
3769 static void checkTemplatePartialSpecialization(Sema &S,
3770 PartialSpecDecl *Partial) {
3771 // C++1z [temp.class.spec]p8: (DR1495)
3772 // - The specialization shall be more specialized than the primary
3773 // template (14.5.5.2).
3774 checkMoreSpecializedThanPrimary(S, Partial);
3776 // C++ [temp.class.spec]p8: (DR1315)
3777 // - Each template-parameter shall appear at least once in the
3778 // template-id outside a non-deduced context.
3779 // C++1z [temp.class.spec.match]p3 (P0127R2)
3780 // If the template arguments of a partial specialization cannot be
3781 // deduced because of the structure of its template-parameter-list
3782 // and the template-id, the program is ill-formed.
3783 auto *TemplateParams = Partial->getTemplateParameters();
3784 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3785 S.MarkUsedTemplateParameters(Partial->getTemplateArgs(), true,
3786 TemplateParams->getDepth(), DeducibleParams);
3788 if (!DeducibleParams.all()) {
3789 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3790 S.Diag(Partial->getLocation(), diag::ext_partial_specs_not_deducible)
3791 << isa<VarTemplatePartialSpecializationDecl>(Partial)
3792 << (NumNonDeducible > 1)
3793 << SourceRange(Partial->getLocation(),
3794 Partial->getTemplateArgsAsWritten()->RAngleLoc);
3795 noteNonDeducibleParameters(S, TemplateParams, DeducibleParams);
3799 void Sema::CheckTemplatePartialSpecialization(
3800 ClassTemplatePartialSpecializationDecl *Partial) {
3801 checkTemplatePartialSpecialization(*this, Partial);
3804 void Sema::CheckTemplatePartialSpecialization(
3805 VarTemplatePartialSpecializationDecl *Partial) {
3806 checkTemplatePartialSpecialization(*this, Partial);
3809 void Sema::CheckDeductionGuideTemplate(FunctionTemplateDecl *TD) {
3810 // C++1z [temp.param]p11:
3811 // A template parameter of a deduction guide template that does not have a
3812 // default-argument shall be deducible from the parameter-type-list of the
3813 // deduction guide template.
3814 auto *TemplateParams = TD->getTemplateParameters();
3815 llvm::SmallBitVector DeducibleParams(TemplateParams->size());
3816 MarkDeducedTemplateParameters(TD, DeducibleParams);
3817 for (unsigned I = 0; I != TemplateParams->size(); ++I) {
3818 // A parameter pack is deducible (to an empty pack).
3819 auto *Param = TemplateParams->getParam(I);
3820 if (Param->isParameterPack() || hasVisibleDefaultArgument(Param))
3821 DeducibleParams[I] = true;
3824 if (!DeducibleParams.all()) {
3825 unsigned NumNonDeducible = DeducibleParams.size() - DeducibleParams.count();
3826 Diag(TD->getLocation(), diag::err_deduction_guide_template_not_deducible)
3827 << (NumNonDeducible > 1);
3828 noteNonDeducibleParameters(*this, TemplateParams, DeducibleParams);
3832 DeclResult Sema::ActOnVarTemplateSpecialization(
3833 Scope *S, Declarator &D, TypeSourceInfo *DI, SourceLocation TemplateKWLoc,
3834 TemplateParameterList *TemplateParams, StorageClass SC,
3835 bool IsPartialSpecialization) {
3836 // D must be variable template id.
3837 assert(D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId &&
3838 "Variable template specialization is declared with a template it.");
3840 TemplateIdAnnotation *TemplateId = D.getName().TemplateId;
3841 TemplateArgumentListInfo TemplateArgs =
3842 makeTemplateArgumentListInfo(*this, *TemplateId);
3843 SourceLocation TemplateNameLoc = D.getIdentifierLoc();
3844 SourceLocation LAngleLoc = TemplateId->LAngleLoc;
3845 SourceLocation RAngleLoc = TemplateId->RAngleLoc;
3847 TemplateName Name = TemplateId->Template.get();
3849 // The template-id must name a variable template.
3850 VarTemplateDecl *VarTemplate =
3851 dyn_cast_or_null<VarTemplateDecl>(Name.getAsTemplateDecl());
3853 NamedDecl *FnTemplate;
3854 if (auto *OTS = Name.getAsOverloadedTemplate())
3855 FnTemplate = *OTS->begin();
3857 FnTemplate = dyn_cast_or_null<FunctionTemplateDecl>(Name.getAsTemplateDecl());
3859 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template_but_method)
3860 << FnTemplate->getDeclName();
3861 return Diag(D.getIdentifierLoc(), diag::err_var_spec_no_template)
3862 << IsPartialSpecialization;
3865 // Check for unexpanded parameter packs in any of the template arguments.
3866 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
3867 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
3868 UPPC_PartialSpecialization))
3871 // Check that the template argument list is well-formed for this
3873 SmallVector<TemplateArgument, 4> Converted;
3874 if (CheckTemplateArgumentList(VarTemplate, TemplateNameLoc, TemplateArgs,
3878 // Find the variable template (partial) specialization declaration that
3879 // corresponds to these arguments.
3880 if (IsPartialSpecialization) {
3881 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, VarTemplate,
3882 TemplateArgs.size(), Converted))
3885 // FIXME: Move these checks to CheckTemplatePartialSpecializationArgs so we
3886 // also do them during instantiation.
3887 bool InstantiationDependent;
3888 if (!Name.isDependent() &&
3889 !TemplateSpecializationType::anyDependentTemplateArguments(
3890 TemplateArgs.arguments(),
3891 InstantiationDependent)) {
3892 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
3893 << VarTemplate->getDeclName();
3894 IsPartialSpecialization = false;
3897 if (isSameAsPrimaryTemplate(VarTemplate->getTemplateParameters(),
3899 // C++ [temp.class.spec]p9b3:
3901 // -- The argument list of the specialization shall not be identical
3902 // to the implicit argument list of the primary template.
3903 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
3904 << /*variable template*/ 1
3905 << /*is definition*/(SC != SC_Extern && !CurContext->isRecord())
3906 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
3907 // FIXME: Recover from this by treating the declaration as a redeclaration
3908 // of the primary template.
3913 void *InsertPos = nullptr;
3914 VarTemplateSpecializationDecl *PrevDecl = nullptr;
3916 if (IsPartialSpecialization)
3917 // FIXME: Template parameter list matters too
3918 PrevDecl = VarTemplate->findPartialSpecialization(Converted, InsertPos);
3920 PrevDecl = VarTemplate->findSpecialization(Converted, InsertPos);
3922 VarTemplateSpecializationDecl *Specialization = nullptr;
3924 // Check whether we can declare a variable template specialization in
3925 // the current scope.
3926 if (CheckTemplateSpecializationScope(*this, VarTemplate, PrevDecl,
3928 IsPartialSpecialization))
3931 if (PrevDecl && PrevDecl->getSpecializationKind() == TSK_Undeclared) {
3932 // Since the only prior variable template specialization with these
3933 // arguments was referenced but not declared, reuse that
3934 // declaration node as our own, updating its source location and
3935 // the list of outer template parameters to reflect our new declaration.
3936 Specialization = PrevDecl;
3937 Specialization->setLocation(TemplateNameLoc);
3939 } else if (IsPartialSpecialization) {
3940 // Create a new class template partial specialization declaration node.
3941 VarTemplatePartialSpecializationDecl *PrevPartial =
3942 cast_or_null<VarTemplatePartialSpecializationDecl>(PrevDecl);
3943 VarTemplatePartialSpecializationDecl *Partial =
3944 VarTemplatePartialSpecializationDecl::Create(
3945 Context, VarTemplate->getDeclContext(), TemplateKWLoc,
3946 TemplateNameLoc, TemplateParams, VarTemplate, DI->getType(), DI, SC,
3947 Converted, TemplateArgs);
3950 VarTemplate->AddPartialSpecialization(Partial, InsertPos);
3951 Specialization = Partial;
3953 // If we are providing an explicit specialization of a member variable
3954 // template specialization, make a note of that.
3955 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
3956 PrevPartial->setMemberSpecialization();
3958 CheckTemplatePartialSpecialization(Partial);
3960 // Create a new class template specialization declaration node for
3961 // this explicit specialization or friend declaration.
3962 Specialization = VarTemplateSpecializationDecl::Create(
3963 Context, VarTemplate->getDeclContext(), TemplateKWLoc, TemplateNameLoc,
3964 VarTemplate, DI->getType(), DI, SC, Converted);
3965 Specialization->setTemplateArgsInfo(TemplateArgs);
3968 VarTemplate->AddSpecialization(Specialization, InsertPos);
3971 // C++ [temp.expl.spec]p6:
3972 // If a template, a member template or the member of a class template is
3973 // explicitly specialized then that specialization shall be declared
3974 // before the first use of that specialization that would cause an implicit
3975 // instantiation to take place, in every translation unit in which such a
3976 // use occurs; no diagnostic is required.
3977 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
3979 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
3980 // Is there any previous explicit specialization declaration?
3981 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
3988 SourceRange Range(TemplateNameLoc, RAngleLoc);
3989 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
3992 Diag(PrevDecl->getPointOfInstantiation(),
3993 diag::note_instantiation_required_here)
3994 << (PrevDecl->getTemplateSpecializationKind() !=
3995 TSK_ImplicitInstantiation);
4000 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
4001 Specialization->setLexicalDeclContext(CurContext);
4003 // Add the specialization into its lexical context, so that it can
4004 // be seen when iterating through the list of declarations in that
4005 // context. However, specializations are not found by name lookup.
4006 CurContext->addDecl(Specialization);
4008 // Note that this is an explicit specialization.
4009 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
4012 // Check that this isn't a redefinition of this specialization,
4013 // merging with previous declarations.
4014 LookupResult PrevSpec(*this, GetNameForDeclarator(D), LookupOrdinaryName,
4015 forRedeclarationInCurContext());
4016 PrevSpec.addDecl(PrevDecl);
4017 D.setRedeclaration(CheckVariableDeclaration(Specialization, PrevSpec));
4018 } else if (Specialization->isStaticDataMember() &&
4019 Specialization->isOutOfLine()) {
4020 Specialization->setAccess(VarTemplate->getAccess());
4023 return Specialization;
4027 /// A partial specialization whose template arguments have matched
4028 /// a given template-id.
4029 struct PartialSpecMatchResult {
4030 VarTemplatePartialSpecializationDecl *Partial;
4031 TemplateArgumentList *Args;
4033 } // end anonymous namespace
4036 Sema::CheckVarTemplateId(VarTemplateDecl *Template, SourceLocation TemplateLoc,
4037 SourceLocation TemplateNameLoc,
4038 const TemplateArgumentListInfo &TemplateArgs) {
4039 assert(Template && "A variable template id without template?");
4041 // Check that the template argument list is well-formed for this template.
4042 SmallVector<TemplateArgument, 4> Converted;
4043 if (CheckTemplateArgumentList(
4044 Template, TemplateNameLoc,
4045 const_cast<TemplateArgumentListInfo &>(TemplateArgs), false,
4049 // Find the variable template specialization declaration that
4050 // corresponds to these arguments.
4051 void *InsertPos = nullptr;
4052 if (VarTemplateSpecializationDecl *Spec = Template->findSpecialization(
4053 Converted, InsertPos)) {
4054 checkSpecializationVisibility(TemplateNameLoc, Spec);
4055 // If we already have a variable template specialization, return it.
4059 // This is the first time we have referenced this variable template
4060 // specialization. Create the canonical declaration and add it to
4061 // the set of specializations, based on the closest partial specialization
4062 // that it represents. That is,
4063 VarDecl *InstantiationPattern = Template->getTemplatedDecl();
4064 TemplateArgumentList TemplateArgList(TemplateArgumentList::OnStack,
4066 TemplateArgumentList *InstantiationArgs = &TemplateArgList;
4067 bool AmbiguousPartialSpec = false;
4068 typedef PartialSpecMatchResult MatchResult;
4069 SmallVector<MatchResult, 4> Matched;
4070 SourceLocation PointOfInstantiation = TemplateNameLoc;
4071 TemplateSpecCandidateSet FailedCandidates(PointOfInstantiation,
4072 /*ForTakingAddress=*/false);
4074 // 1. Attempt to find the closest partial specialization that this
4075 // specializes, if any.
4076 // If any of the template arguments is dependent, then this is probably
4077 // a placeholder for an incomplete declarative context; which must be
4078 // complete by instantiation time. Thus, do not search through the partial
4079 // specializations yet.
4080 // TODO: Unify with InstantiateClassTemplateSpecialization()?
4081 // Perhaps better after unification of DeduceTemplateArguments() and
4082 // getMoreSpecializedPartialSpecialization().
4083 bool InstantiationDependent = false;
4084 if (!TemplateSpecializationType::anyDependentTemplateArguments(
4085 TemplateArgs, InstantiationDependent)) {
4087 SmallVector<VarTemplatePartialSpecializationDecl *, 4> PartialSpecs;
4088 Template->getPartialSpecializations(PartialSpecs);
4090 for (unsigned I = 0, N = PartialSpecs.size(); I != N; ++I) {
4091 VarTemplatePartialSpecializationDecl *Partial = PartialSpecs[I];
4092 TemplateDeductionInfo Info(FailedCandidates.getLocation());
4094 if (TemplateDeductionResult Result =
4095 DeduceTemplateArguments(Partial, TemplateArgList, Info)) {
4096 // Store the failed-deduction information for use in diagnostics, later.
4097 // TODO: Actually use the failed-deduction info?
4098 FailedCandidates.addCandidate().set(
4099 DeclAccessPair::make(Template, AS_public), Partial,
4100 MakeDeductionFailureInfo(Context, Result, Info));
4103 Matched.push_back(PartialSpecMatchResult());
4104 Matched.back().Partial = Partial;
4105 Matched.back().Args = Info.take();
4109 if (Matched.size() >= 1) {
4110 SmallVector<MatchResult, 4>::iterator Best = Matched.begin();
4111 if (Matched.size() == 1) {
4112 // -- If exactly one matching specialization is found, the
4113 // instantiation is generated from that specialization.
4114 // We don't need to do anything for this.
4116 // -- If more than one matching specialization is found, the
4117 // partial order rules (14.5.4.2) are used to determine
4118 // whether one of the specializations is more specialized
4119 // than the others. If none of the specializations is more
4120 // specialized than all of the other matching
4121 // specializations, then the use of the variable template is
4122 // ambiguous and the program is ill-formed.
4123 for (SmallVector<MatchResult, 4>::iterator P = Best + 1,
4124 PEnd = Matched.end();
4126 if (getMoreSpecializedPartialSpecialization(P->Partial, Best->Partial,
4127 PointOfInstantiation) ==
4132 // Determine if the best partial specialization is more specialized than
4134 for (SmallVector<MatchResult, 4>::iterator P = Matched.begin(),
4135 PEnd = Matched.end();
4137 if (P != Best && getMoreSpecializedPartialSpecialization(
4138 P->Partial, Best->Partial,
4139 PointOfInstantiation) != Best->Partial) {
4140 AmbiguousPartialSpec = true;
4146 // Instantiate using the best variable template partial specialization.
4147 InstantiationPattern = Best->Partial;
4148 InstantiationArgs = Best->Args;
4150 // -- If no match is found, the instantiation is generated
4151 // from the primary template.
4152 // InstantiationPattern = Template->getTemplatedDecl();
4156 // 2. Create the canonical declaration.
4157 // Note that we do not instantiate a definition until we see an odr-use
4158 // in DoMarkVarDeclReferenced().
4159 // FIXME: LateAttrs et al.?
4160 VarTemplateSpecializationDecl *Decl = BuildVarTemplateInstantiation(
4161 Template, InstantiationPattern, *InstantiationArgs, TemplateArgs,
4162 Converted, TemplateNameLoc, InsertPos /*, LateAttrs, StartingScope*/);
4166 if (AmbiguousPartialSpec) {
4167 // Partial ordering did not produce a clear winner. Complain.
4168 Decl->setInvalidDecl();
4169 Diag(PointOfInstantiation, diag::err_partial_spec_ordering_ambiguous)
4172 // Print the matching partial specializations.
4173 for (MatchResult P : Matched)
4174 Diag(P.Partial->getLocation(), diag::note_partial_spec_match)
4175 << getTemplateArgumentBindingsText(P.Partial->getTemplateParameters(),
4180 if (VarTemplatePartialSpecializationDecl *D =
4181 dyn_cast<VarTemplatePartialSpecializationDecl>(InstantiationPattern))
4182 Decl->setInstantiationOf(D, InstantiationArgs);
4184 checkSpecializationVisibility(TemplateNameLoc, Decl);
4186 assert(Decl && "No variable template specialization?");
4191 Sema::CheckVarTemplateId(const CXXScopeSpec &SS,
4192 const DeclarationNameInfo &NameInfo,
4193 VarTemplateDecl *Template, SourceLocation TemplateLoc,
4194 const TemplateArgumentListInfo *TemplateArgs) {
4196 DeclResult Decl = CheckVarTemplateId(Template, TemplateLoc, NameInfo.getLoc(),
4198 if (Decl.isInvalid())
4201 VarDecl *Var = cast<VarDecl>(Decl.get());
4202 if (!Var->getTemplateSpecializationKind())
4203 Var->setTemplateSpecializationKind(TSK_ImplicitInstantiation,
4206 // Build an ordinary singleton decl ref.
4207 return BuildDeclarationNameExpr(SS, NameInfo, Var,
4208 /*FoundD=*/nullptr, TemplateArgs);
4211 void Sema::diagnoseMissingTemplateArguments(TemplateName Name,
4212 SourceLocation Loc) {
4213 Diag(Loc, diag::err_template_missing_args)
4214 << (int)getTemplateNameKindForDiagnostics(Name) << Name;
4215 if (TemplateDecl *TD = Name.getAsTemplateDecl()) {
4216 Diag(TD->getLocation(), diag::note_template_decl_here)
4217 << TD->getTemplateParameters()->getSourceRange();
4222 Sema::CheckConceptTemplateId(const CXXScopeSpec &SS,
4223 SourceLocation TemplateKWLoc,
4224 SourceLocation ConceptNameLoc,
4225 NamedDecl *FoundDecl,
4226 ConceptDecl *NamedConcept,
4227 const TemplateArgumentListInfo *TemplateArgs) {
4228 assert(NamedConcept && "A concept template id without a template?");
4230 llvm::SmallVector<TemplateArgument, 4> Converted;
4231 if (CheckTemplateArgumentList(NamedConcept, ConceptNameLoc,
4232 const_cast<TemplateArgumentListInfo&>(*TemplateArgs),
4233 /*PartialTemplateArgs=*/false, Converted,
4234 /*UpdateArgsWithConversion=*/false))
4237 Optional<bool> IsSatisfied;
4238 bool AreArgsDependent = false;
4239 for (TemplateArgument &Arg : Converted) {
4240 if (Arg.isDependent()) {
4241 AreArgsDependent = true;
4245 if (!AreArgsDependent) {
4246 InstantiatingTemplate Inst(*this, ConceptNameLoc,
4247 InstantiatingTemplate::ConstraintsCheck{}, NamedConcept, Converted,
4248 SourceRange(SS.isSet() ? SS.getBeginLoc() : ConceptNameLoc,
4249 TemplateArgs->getRAngleLoc()));
4250 MultiLevelTemplateArgumentList MLTAL;
4251 MLTAL.addOuterTemplateArguments(Converted);
4253 if (CalculateConstraintSatisfaction(NamedConcept, MLTAL,
4254 NamedConcept->getConstraintExpr(),
4257 IsSatisfied = Satisfied;
4259 return ConceptSpecializationExpr::Create(Context,
4260 SS.isSet() ? SS.getWithLocInContext(Context) : NestedNameSpecifierLoc{},
4261 TemplateKWLoc, ConceptNameLoc, FoundDecl, NamedConcept,
4262 ASTTemplateArgumentListInfo::Create(Context, *TemplateArgs), Converted,
4266 ExprResult Sema::BuildTemplateIdExpr(const CXXScopeSpec &SS,
4267 SourceLocation TemplateKWLoc,
4270 const TemplateArgumentListInfo *TemplateArgs) {
4271 // FIXME: Can we do any checking at this point? I guess we could check the
4272 // template arguments that we have against the template name, if the template
4273 // name refers to a single template. That's not a terribly common case,
4275 // foo<int> could identify a single function unambiguously
4276 // This approach does NOT work, since f<int>(1);
4277 // gets resolved prior to resorting to overload resolution
4278 // i.e., template<class T> void f(double);
4279 // vs template<class T, class U> void f(U);
4281 // These should be filtered out by our callers.
4282 assert(!R.isAmbiguous() && "ambiguous lookup when building templateid");
4284 // Non-function templates require a template argument list.
4285 if (auto *TD = R.getAsSingle<TemplateDecl>()) {
4286 if (!TemplateArgs && !isa<FunctionTemplateDecl>(TD)) {
4287 diagnoseMissingTemplateArguments(TemplateName(TD), R.getNameLoc());
4292 auto AnyDependentArguments = [&]() -> bool {
4293 bool InstantiationDependent;
4294 return TemplateArgs &&
4295 TemplateSpecializationType::anyDependentTemplateArguments(
4296 *TemplateArgs, InstantiationDependent);
4299 // In C++1y, check variable template ids.
4300 if (R.getAsSingle<VarTemplateDecl>() && !AnyDependentArguments()) {
4301 return CheckVarTemplateId(SS, R.getLookupNameInfo(),
4302 R.getAsSingle<VarTemplateDecl>(),
4303 TemplateKWLoc, TemplateArgs);
4306 if (R.getAsSingle<ConceptDecl>()) {
4307 return CheckConceptTemplateId(SS, TemplateKWLoc,
4308 R.getLookupNameInfo().getBeginLoc(),
4310 R.getAsSingle<ConceptDecl>(), TemplateArgs);
4313 // We don't want lookup warnings at this point.
4314 R.suppressDiagnostics();
4316 UnresolvedLookupExpr *ULE
4317 = UnresolvedLookupExpr::Create(Context, R.getNamingClass(),
4318 SS.getWithLocInContext(Context),
4320 R.getLookupNameInfo(),
4321 RequiresADL, TemplateArgs,
4322 R.begin(), R.end());
4327 // We actually only call this from template instantiation.
4329 Sema::BuildQualifiedTemplateIdExpr(CXXScopeSpec &SS,
4330 SourceLocation TemplateKWLoc,
4331 const DeclarationNameInfo &NameInfo,
4332 const TemplateArgumentListInfo *TemplateArgs) {
4334 assert(TemplateArgs || TemplateKWLoc.isValid());
4336 if (!(DC = computeDeclContext(SS, false)) ||
4337 DC->isDependentContext() ||
4338 RequireCompleteDeclContext(SS, DC))
4339 return BuildDependentDeclRefExpr(SS, TemplateKWLoc, NameInfo, TemplateArgs);
4341 bool MemberOfUnknownSpecialization;
4342 LookupResult R(*this, NameInfo, LookupOrdinaryName);
4343 if (LookupTemplateName(R, (Scope *)nullptr, SS, QualType(),
4344 /*Entering*/false, MemberOfUnknownSpecialization,
4348 if (R.isAmbiguous())
4352 Diag(NameInfo.getLoc(), diag::err_no_member)
4353 << NameInfo.getName() << DC << SS.getRange();
4357 if (ClassTemplateDecl *Temp = R.getAsSingle<ClassTemplateDecl>()) {
4358 Diag(NameInfo.getLoc(), diag::err_template_kw_refers_to_class_template)
4360 << NameInfo.getName().getAsString() << SS.getRange();
4361 Diag(Temp->getLocation(), diag::note_referenced_class_template);
4365 return BuildTemplateIdExpr(SS, TemplateKWLoc, R, /*ADL*/ false, TemplateArgs);
4368 /// Form a dependent template name.
4370 /// This action forms a dependent template name given the template
4371 /// name and its (presumably dependent) scope specifier. For
4372 /// example, given "MetaFun::template apply", the scope specifier \p
4373 /// SS will be "MetaFun::", \p TemplateKWLoc contains the location
4374 /// of the "template" keyword, and "apply" is the \p Name.
4375 TemplateNameKind Sema::ActOnDependentTemplateName(Scope *S,
4377 SourceLocation TemplateKWLoc,
4378 const UnqualifiedId &Name,
4379 ParsedType ObjectType,
4380 bool EnteringContext,
4382 bool AllowInjectedClassName) {
4383 if (TemplateKWLoc.isValid() && S && !S->getTemplateParamParent())
4385 getLangOpts().CPlusPlus11 ?
4386 diag::warn_cxx98_compat_template_outside_of_template :
4387 diag::ext_template_outside_of_template)
4388 << FixItHint::CreateRemoval(TemplateKWLoc);
4390 DeclContext *LookupCtx = nullptr;
4392 LookupCtx = computeDeclContext(SS, EnteringContext);
4393 if (!LookupCtx && ObjectType)
4394 LookupCtx = computeDeclContext(ObjectType.get());
4396 // C++0x [temp.names]p5:
4397 // If a name prefixed by the keyword template is not the name of
4398 // a template, the program is ill-formed. [Note: the keyword
4399 // template may not be applied to non-template members of class
4400 // templates. -end note ] [ Note: as is the case with the
4401 // typename prefix, the template prefix is allowed in cases
4402 // where it is not strictly necessary; i.e., when the
4403 // nested-name-specifier or the expression on the left of the ->
4404 // or . is not dependent on a template-parameter, or the use
4405 // does not appear in the scope of a template. -end note]
4407 // Note: C++03 was more strict here, because it banned the use of
4408 // the "template" keyword prior to a template-name that was not a
4409 // dependent name. C++ DR468 relaxed this requirement (the
4410 // "template" keyword is now permitted). We follow the C++0x
4411 // rules, even in C++03 mode with a warning, retroactively applying the DR.
4412 bool MemberOfUnknownSpecialization;
4413 TemplateNameKind TNK = isTemplateName(S, SS, TemplateKWLoc.isValid(), Name,
4414 ObjectType, EnteringContext, Result,
4415 MemberOfUnknownSpecialization);
4416 if (TNK == TNK_Non_template && MemberOfUnknownSpecialization) {
4417 // This is a dependent template. Handle it below.
4418 } else if (TNK == TNK_Non_template) {
4419 // Do the lookup again to determine if this is a "nothing found" case or
4420 // a "not a template" case. FIXME: Refactor isTemplateName so we don't
4422 DeclarationNameInfo DNI = GetNameFromUnqualifiedId(Name);
4423 LookupResult R(*this, DNI.getName(), Name.getBeginLoc(),
4424 LookupOrdinaryName);
4426 if (!LookupTemplateName(R, S, SS, ObjectType.get(), EnteringContext,
4427 MOUS, TemplateKWLoc) && !R.isAmbiguous())
4428 Diag(Name.getBeginLoc(), diag::err_no_member)
4429 << DNI.getName() << LookupCtx << SS.getRange();
4430 return TNK_Non_template;
4432 // We found something; return it.
4433 auto *LookupRD = dyn_cast<CXXRecordDecl>(LookupCtx);
4434 if (!AllowInjectedClassName && SS.isSet() && LookupRD &&
4435 Name.getKind() == UnqualifiedIdKind::IK_Identifier &&
4436 Name.Identifier && LookupRD->getIdentifier() == Name.Identifier) {
4437 // C++14 [class.qual]p2:
4438 // In a lookup in which function names are not ignored and the
4439 // nested-name-specifier nominates a class C, if the name specified
4440 // [...] is the injected-class-name of C, [...] the name is instead
4441 // considered to name the constructor
4443 // We don't get here if naming the constructor would be valid, so we
4444 // just reject immediately and recover by treating the
4445 // injected-class-name as naming the template.
4446 Diag(Name.getBeginLoc(),
4447 diag::ext_out_of_line_qualified_id_type_names_constructor)
4449 << 0 /*injected-class-name used as template name*/
4450 << 1 /*'template' keyword was used*/;
4456 NestedNameSpecifier *Qualifier = SS.getScopeRep();
4458 switch (Name.getKind()) {
4459 case UnqualifiedIdKind::IK_Identifier:
4460 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4462 return TNK_Dependent_template_name;
4464 case UnqualifiedIdKind::IK_OperatorFunctionId:
4465 Result = TemplateTy::make(Context.getDependentTemplateName(Qualifier,
4466 Name.OperatorFunctionId.Operator));
4467 return TNK_Function_template;
4469 case UnqualifiedIdKind::IK_LiteralOperatorId:
4470 llvm_unreachable("literal operator id cannot have a dependent scope");
4476 Diag(Name.getBeginLoc(), diag::err_template_kw_refers_to_non_template)
4477 << GetNameFromUnqualifiedId(Name).getName() << Name.getSourceRange()
4479 return TNK_Non_template;
4482 bool Sema::CheckTemplateTypeArgument(TemplateTypeParmDecl *Param,
4483 TemplateArgumentLoc &AL,
4484 SmallVectorImpl<TemplateArgument> &Converted) {
4485 const TemplateArgument &Arg = AL.getArgument();
4487 TypeSourceInfo *TSI = nullptr;
4489 // Check template type parameter.
4490 switch(Arg.getKind()) {
4491 case TemplateArgument::Type:
4492 // C++ [temp.arg.type]p1:
4493 // A template-argument for a template-parameter which is a
4494 // type shall be a type-id.
4495 ArgType = Arg.getAsType();
4496 TSI = AL.getTypeSourceInfo();
4498 case TemplateArgument::Template:
4499 case TemplateArgument::TemplateExpansion: {
4500 // We have a template type parameter but the template argument
4501 // is a template without any arguments.
4502 SourceRange SR = AL.getSourceRange();
4503 TemplateName Name = Arg.getAsTemplateOrTemplatePattern();
4504 diagnoseMissingTemplateArguments(Name, SR.getEnd());
4507 case TemplateArgument::Expression: {
4508 // We have a template type parameter but the template argument is an
4509 // expression; see if maybe it is missing the "typename" keyword.
4511 DeclarationNameInfo NameInfo;
4513 if (DeclRefExpr *ArgExpr = dyn_cast<DeclRefExpr>(Arg.getAsExpr())) {
4514 SS.Adopt(ArgExpr->getQualifierLoc());
4515 NameInfo = ArgExpr->getNameInfo();
4516 } else if (DependentScopeDeclRefExpr *ArgExpr =
4517 dyn_cast<DependentScopeDeclRefExpr>(Arg.getAsExpr())) {
4518 SS.Adopt(ArgExpr->getQualifierLoc());
4519 NameInfo = ArgExpr->getNameInfo();
4520 } else if (CXXDependentScopeMemberExpr *ArgExpr =
4521 dyn_cast<CXXDependentScopeMemberExpr>(Arg.getAsExpr())) {
4522 if (ArgExpr->isImplicitAccess()) {
4523 SS.Adopt(ArgExpr->getQualifierLoc());
4524 NameInfo = ArgExpr->getMemberNameInfo();
4528 if (auto *II = NameInfo.getName().getAsIdentifierInfo()) {
4529 LookupResult Result(*this, NameInfo, LookupOrdinaryName);
4530 LookupParsedName(Result, CurScope, &SS);
4532 if (Result.getAsSingle<TypeDecl>() ||
4533 Result.getResultKind() ==
4534 LookupResult::NotFoundInCurrentInstantiation) {
4535 // Suggest that the user add 'typename' before the NNS.
4536 SourceLocation Loc = AL.getSourceRange().getBegin();
4537 Diag(Loc, getLangOpts().MSVCCompat
4538 ? diag::ext_ms_template_type_arg_missing_typename
4539 : diag::err_template_arg_must_be_type_suggest)
4540 << FixItHint::CreateInsertion(Loc, "typename ");
4541 Diag(Param->getLocation(), diag::note_template_param_here);
4543 // Recover by synthesizing a type using the location information that we
4546 Context.getDependentNameType(ETK_Typename, SS.getScopeRep(), II);
4548 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(ArgType);
4549 TL.setElaboratedKeywordLoc(SourceLocation(/*synthesized*/));
4550 TL.setQualifierLoc(SS.getWithLocInContext(Context));
4551 TL.setNameLoc(NameInfo.getLoc());
4552 TSI = TLB.getTypeSourceInfo(Context, ArgType);
4554 // Overwrite our input TemplateArgumentLoc so that we can recover
4556 AL = TemplateArgumentLoc(TemplateArgument(ArgType),
4557 TemplateArgumentLocInfo(TSI));
4566 // We have a template type parameter but the template argument
4568 SourceRange SR = AL.getSourceRange();
4569 Diag(SR.getBegin(), diag::err_template_arg_must_be_type) << SR;
4570 Diag(Param->getLocation(), diag::note_template_param_here);
4576 if (CheckTemplateArgument(Param, TSI))
4579 // Add the converted template type argument.
4580 ArgType = Context.getCanonicalType(ArgType);
4583 // If an explicitly-specified template argument type is a lifetime type
4584 // with no lifetime qualifier, the __strong lifetime qualifier is inferred.
4585 if (getLangOpts().ObjCAutoRefCount &&
4586 ArgType->isObjCLifetimeType() &&
4587 !ArgType.getObjCLifetime()) {
4589 Qs.setObjCLifetime(Qualifiers::OCL_Strong);
4590 ArgType = Context.getQualifiedType(ArgType, Qs);
4593 Converted.push_back(TemplateArgument(ArgType));
4597 /// Substitute template arguments into the default template argument for
4598 /// the given template type parameter.
4600 /// \param SemaRef the semantic analysis object for which we are performing
4601 /// the substitution.
4603 /// \param Template the template that we are synthesizing template arguments
4606 /// \param TemplateLoc the location of the template name that started the
4607 /// template-id we are checking.
4609 /// \param RAngleLoc the location of the right angle bracket ('>') that
4610 /// terminates the template-id.
4612 /// \param Param the template template parameter whose default we are
4613 /// substituting into.
4615 /// \param Converted the list of template arguments provided for template
4616 /// parameters that precede \p Param in the template parameter list.
4617 /// \returns the substituted template argument, or NULL if an error occurred.
4618 static TypeSourceInfo *
4619 SubstDefaultTemplateArgument(Sema &SemaRef,
4620 TemplateDecl *Template,
4621 SourceLocation TemplateLoc,
4622 SourceLocation RAngleLoc,
4623 TemplateTypeParmDecl *Param,
4624 SmallVectorImpl<TemplateArgument> &Converted) {
4625 TypeSourceInfo *ArgType = Param->getDefaultArgumentInfo();
4627 // If the argument type is dependent, instantiate it now based
4628 // on the previously-computed template arguments.
4629 if (ArgType->getType()->isInstantiationDependentType()) {
4630 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4631 Param, Template, Converted,
4632 SourceRange(TemplateLoc, RAngleLoc));
4633 if (Inst.isInvalid())
4636 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4638 // Only substitute for the innermost template argument list.
4639 MultiLevelTemplateArgumentList TemplateArgLists;
4640 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4641 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4642 TemplateArgLists.addOuterTemplateArguments(None);
4644 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4646 SemaRef.SubstType(ArgType, TemplateArgLists,
4647 Param->getDefaultArgumentLoc(), Param->getDeclName());
4653 /// Substitute template arguments into the default template argument for
4654 /// the given non-type template parameter.
4656 /// \param SemaRef the semantic analysis object for which we are performing
4657 /// the substitution.
4659 /// \param Template the template that we are synthesizing template arguments
4662 /// \param TemplateLoc the location of the template name that started the
4663 /// template-id we are checking.
4665 /// \param RAngleLoc the location of the right angle bracket ('>') that
4666 /// terminates the template-id.
4668 /// \param Param the non-type template parameter whose default we are
4669 /// substituting into.
4671 /// \param Converted the list of template arguments provided for template
4672 /// parameters that precede \p Param in the template parameter list.
4674 /// \returns the substituted template argument, or NULL if an error occurred.
4676 SubstDefaultTemplateArgument(Sema &SemaRef,
4677 TemplateDecl *Template,
4678 SourceLocation TemplateLoc,
4679 SourceLocation RAngleLoc,
4680 NonTypeTemplateParmDecl *Param,
4681 SmallVectorImpl<TemplateArgument> &Converted) {
4682 Sema::InstantiatingTemplate Inst(SemaRef, TemplateLoc,
4683 Param, Template, Converted,
4684 SourceRange(TemplateLoc, RAngleLoc));
4685 if (Inst.isInvalid())
4688 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4690 // Only substitute for the innermost template argument list.
4691 MultiLevelTemplateArgumentList TemplateArgLists;
4692 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4693 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4694 TemplateArgLists.addOuterTemplateArguments(None);
4696 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4697 EnterExpressionEvaluationContext ConstantEvaluated(
4698 SemaRef, Sema::ExpressionEvaluationContext::ConstantEvaluated);
4699 return SemaRef.SubstExpr(Param->getDefaultArgument(), TemplateArgLists);
4702 /// Substitute template arguments into the default template argument for
4703 /// the given template template parameter.
4705 /// \param SemaRef the semantic analysis object for which we are performing
4706 /// the substitution.
4708 /// \param Template the template that we are synthesizing template arguments
4711 /// \param TemplateLoc the location of the template name that started the
4712 /// template-id we are checking.
4714 /// \param RAngleLoc the location of the right angle bracket ('>') that
4715 /// terminates the template-id.
4717 /// \param Param the template template parameter whose default we are
4718 /// substituting into.
4720 /// \param Converted the list of template arguments provided for template
4721 /// parameters that precede \p Param in the template parameter list.
4723 /// \param QualifierLoc Will be set to the nested-name-specifier (with
4724 /// source-location information) that precedes the template name.
4726 /// \returns the substituted template argument, or NULL if an error occurred.
4728 SubstDefaultTemplateArgument(Sema &SemaRef,
4729 TemplateDecl *Template,
4730 SourceLocation TemplateLoc,
4731 SourceLocation RAngleLoc,
4732 TemplateTemplateParmDecl *Param,
4733 SmallVectorImpl<TemplateArgument> &Converted,
4734 NestedNameSpecifierLoc &QualifierLoc) {
4735 Sema::InstantiatingTemplate Inst(
4736 SemaRef, TemplateLoc, TemplateParameter(Param), Template, Converted,
4737 SourceRange(TemplateLoc, RAngleLoc));
4738 if (Inst.isInvalid())
4739 return TemplateName();
4741 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
4743 // Only substitute for the innermost template argument list.
4744 MultiLevelTemplateArgumentList TemplateArgLists;
4745 TemplateArgLists.addOuterTemplateArguments(&TemplateArgs);
4746 for (unsigned i = 0, e = Param->getDepth(); i != e; ++i)
4747 TemplateArgLists.addOuterTemplateArguments(None);
4749 Sema::ContextRAII SavedContext(SemaRef, Template->getDeclContext());
4750 // Substitute into the nested-name-specifier first,
4751 QualifierLoc = Param->getDefaultArgument().getTemplateQualifierLoc();
4754 SemaRef.SubstNestedNameSpecifierLoc(QualifierLoc, TemplateArgLists);
4756 return TemplateName();
4759 return SemaRef.SubstTemplateName(
4761 Param->getDefaultArgument().getArgument().getAsTemplate(),
4762 Param->getDefaultArgument().getTemplateNameLoc(),
4766 /// If the given template parameter has a default template
4767 /// argument, substitute into that default template argument and
4768 /// return the corresponding template argument.
4770 Sema::SubstDefaultTemplateArgumentIfAvailable(TemplateDecl *Template,
4771 SourceLocation TemplateLoc,
4772 SourceLocation RAngleLoc,
4774 SmallVectorImpl<TemplateArgument>
4776 bool &HasDefaultArg) {
4777 HasDefaultArg = false;
4779 if (TemplateTypeParmDecl *TypeParm = dyn_cast<TemplateTypeParmDecl>(Param)) {
4780 if (!hasVisibleDefaultArgument(TypeParm))
4781 return TemplateArgumentLoc();
4783 HasDefaultArg = true;
4784 TypeSourceInfo *DI = SubstDefaultTemplateArgument(*this, Template,
4790 return TemplateArgumentLoc(TemplateArgument(DI->getType()), DI);
4792 return TemplateArgumentLoc();
4795 if (NonTypeTemplateParmDecl *NonTypeParm
4796 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4797 if (!hasVisibleDefaultArgument(NonTypeParm))
4798 return TemplateArgumentLoc();
4800 HasDefaultArg = true;
4801 ExprResult Arg = SubstDefaultTemplateArgument(*this, Template,
4806 if (Arg.isInvalid())
4807 return TemplateArgumentLoc();
4809 Expr *ArgE = Arg.getAs<Expr>();
4810 return TemplateArgumentLoc(TemplateArgument(ArgE), ArgE);
4813 TemplateTemplateParmDecl *TempTempParm
4814 = cast<TemplateTemplateParmDecl>(Param);
4815 if (!hasVisibleDefaultArgument(TempTempParm))
4816 return TemplateArgumentLoc();
4818 HasDefaultArg = true;
4819 NestedNameSpecifierLoc QualifierLoc;
4820 TemplateName TName = SubstDefaultTemplateArgument(*this, Template,
4827 return TemplateArgumentLoc();
4829 return TemplateArgumentLoc(TemplateArgument(TName),
4830 TempTempParm->getDefaultArgument().getTemplateQualifierLoc(),
4831 TempTempParm->getDefaultArgument().getTemplateNameLoc());
4834 /// Convert a template-argument that we parsed as a type into a template, if
4835 /// possible. C++ permits injected-class-names to perform dual service as
4836 /// template template arguments and as template type arguments.
4837 static TemplateArgumentLoc convertTypeTemplateArgumentToTemplate(TypeLoc TLoc) {
4838 // Extract and step over any surrounding nested-name-specifier.
4839 NestedNameSpecifierLoc QualLoc;
4840 if (auto ETLoc = TLoc.getAs<ElaboratedTypeLoc>()) {
4841 if (ETLoc.getTypePtr()->getKeyword() != ETK_None)
4842 return TemplateArgumentLoc();
4844 QualLoc = ETLoc.getQualifierLoc();
4845 TLoc = ETLoc.getNamedTypeLoc();
4848 // If this type was written as an injected-class-name, it can be used as a
4849 // template template argument.
4850 if (auto InjLoc = TLoc.getAs<InjectedClassNameTypeLoc>())
4851 return TemplateArgumentLoc(InjLoc.getTypePtr()->getTemplateName(),
4852 QualLoc, InjLoc.getNameLoc());
4854 // If this type was written as an injected-class-name, it may have been
4855 // converted to a RecordType during instantiation. If the RecordType is
4856 // *not* wrapped in a TemplateSpecializationType and denotes a class
4857 // template specialization, it must have come from an injected-class-name.
4858 if (auto RecLoc = TLoc.getAs<RecordTypeLoc>())
4860 dyn_cast<ClassTemplateSpecializationDecl>(RecLoc.getDecl()))
4861 return TemplateArgumentLoc(TemplateName(CTSD->getSpecializedTemplate()),
4862 QualLoc, RecLoc.getNameLoc());
4864 return TemplateArgumentLoc();
4867 /// Check that the given template argument corresponds to the given
4868 /// template parameter.
4870 /// \param Param The template parameter against which the argument will be
4873 /// \param Arg The template argument, which may be updated due to conversions.
4875 /// \param Template The template in which the template argument resides.
4877 /// \param TemplateLoc The location of the template name for the template
4878 /// whose argument list we're matching.
4880 /// \param RAngleLoc The location of the right angle bracket ('>') that closes
4881 /// the template argument list.
4883 /// \param ArgumentPackIndex The index into the argument pack where this
4884 /// argument will be placed. Only valid if the parameter is a parameter pack.
4886 /// \param Converted The checked, converted argument will be added to the
4887 /// end of this small vector.
4889 /// \param CTAK Describes how we arrived at this particular template argument:
4890 /// explicitly written, deduced, etc.
4892 /// \returns true on error, false otherwise.
4893 bool Sema::CheckTemplateArgument(NamedDecl *Param,
4894 TemplateArgumentLoc &Arg,
4895 NamedDecl *Template,
4896 SourceLocation TemplateLoc,
4897 SourceLocation RAngleLoc,
4898 unsigned ArgumentPackIndex,
4899 SmallVectorImpl<TemplateArgument> &Converted,
4900 CheckTemplateArgumentKind CTAK) {
4901 // Check template type parameters.
4902 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param))
4903 return CheckTemplateTypeArgument(TTP, Arg, Converted);
4905 // Check non-type template parameters.
4906 if (NonTypeTemplateParmDecl *NTTP =dyn_cast<NonTypeTemplateParmDecl>(Param)) {
4907 // Do substitution on the type of the non-type template parameter
4908 // with the template arguments we've seen thus far. But if the
4909 // template has a dependent context then we cannot substitute yet.
4910 QualType NTTPType = NTTP->getType();
4911 if (NTTP->isParameterPack() && NTTP->isExpandedParameterPack())
4912 NTTPType = NTTP->getExpansionType(ArgumentPackIndex);
4914 if (NTTPType->isInstantiationDependentType() &&
4915 !isa<TemplateTemplateParmDecl>(Template) &&
4916 !Template->getDeclContext()->isDependentContext()) {
4917 // Do substitution on the type of the non-type template parameter.
4918 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
4920 SourceRange(TemplateLoc, RAngleLoc));
4921 if (Inst.isInvalid())
4924 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack,
4927 // If the parameter is a pack expansion, expand this slice of the pack.
4928 if (auto *PET = NTTPType->getAs<PackExpansionType>()) {
4929 Sema::ArgumentPackSubstitutionIndexRAII SubstIndex(*this,
4931 NTTPType = SubstType(PET->getPattern(),
4932 MultiLevelTemplateArgumentList(TemplateArgs),
4933 NTTP->getLocation(),
4934 NTTP->getDeclName());
4936 NTTPType = SubstType(NTTPType,
4937 MultiLevelTemplateArgumentList(TemplateArgs),
4938 NTTP->getLocation(),
4939 NTTP->getDeclName());
4942 // If that worked, check the non-type template parameter type
4944 if (!NTTPType.isNull())
4945 NTTPType = CheckNonTypeTemplateParameterType(NTTPType,
4946 NTTP->getLocation());
4947 if (NTTPType.isNull())
4951 switch (Arg.getArgument().getKind()) {
4952 case TemplateArgument::Null:
4953 llvm_unreachable("Should never see a NULL template argument here");
4955 case TemplateArgument::Expression: {
4956 TemplateArgument Result;
4957 unsigned CurSFINAEErrors = NumSFINAEErrors;
4959 CheckTemplateArgument(NTTP, NTTPType, Arg.getArgument().getAsExpr(),
4961 if (Res.isInvalid())
4963 // If the current template argument causes an error, give up now.
4964 if (CurSFINAEErrors < NumSFINAEErrors)
4967 // If the resulting expression is new, then use it in place of the
4968 // old expression in the template argument.
4969 if (Res.get() != Arg.getArgument().getAsExpr()) {
4970 TemplateArgument TA(Res.get());
4971 Arg = TemplateArgumentLoc(TA, Res.get());
4974 Converted.push_back(Result);
4978 case TemplateArgument::Declaration:
4979 case TemplateArgument::Integral:
4980 case TemplateArgument::NullPtr:
4981 // We've already checked this template argument, so just copy
4982 // it to the list of converted arguments.
4983 Converted.push_back(Arg.getArgument());
4986 case TemplateArgument::Template:
4987 case TemplateArgument::TemplateExpansion:
4988 // We were given a template template argument. It may not be ill-formed;
4990 if (DependentTemplateName *DTN
4991 = Arg.getArgument().getAsTemplateOrTemplatePattern()
4992 .getAsDependentTemplateName()) {
4993 // We have a template argument such as \c T::template X, which we
4994 // parsed as a template template argument. However, since we now
4995 // know that we need a non-type template argument, convert this
4996 // template name into an expression.
4998 DeclarationNameInfo NameInfo(DTN->getIdentifier(),
4999 Arg.getTemplateNameLoc());
5002 SS.Adopt(Arg.getTemplateQualifierLoc());
5003 // FIXME: the template-template arg was a DependentTemplateName,
5004 // so it was provided with a template keyword. However, its source
5005 // location is not stored in the template argument structure.
5006 SourceLocation TemplateKWLoc;
5007 ExprResult E = DependentScopeDeclRefExpr::Create(
5008 Context, SS.getWithLocInContext(Context), TemplateKWLoc, NameInfo,
5011 // If we parsed the template argument as a pack expansion, create a
5012 // pack expansion expression.
5013 if (Arg.getArgument().getKind() == TemplateArgument::TemplateExpansion){
5014 E = ActOnPackExpansion(E.get(), Arg.getTemplateEllipsisLoc());
5019 TemplateArgument Result;
5020 E = CheckTemplateArgument(NTTP, NTTPType, E.get(), Result);
5024 Converted.push_back(Result);
5028 // We have a template argument that actually does refer to a class
5029 // template, alias template, or template template parameter, and
5030 // therefore cannot be a non-type template argument.
5031 Diag(Arg.getLocation(), diag::err_template_arg_must_be_expr)
5032 << Arg.getSourceRange();
5034 Diag(Param->getLocation(), diag::note_template_param_here);
5037 case TemplateArgument::Type: {
5038 // We have a non-type template parameter but the template
5039 // argument is a type.
5041 // C++ [temp.arg]p2:
5042 // In a template-argument, an ambiguity between a type-id and
5043 // an expression is resolved to a type-id, regardless of the
5044 // form of the corresponding template-parameter.
5046 // We warn specifically about this case, since it can be rather
5047 // confusing for users.
5048 QualType T = Arg.getArgument().getAsType();
5049 SourceRange SR = Arg.getSourceRange();
5050 if (T->isFunctionType())
5051 Diag(SR.getBegin(), diag::err_template_arg_nontype_ambig) << SR << T;
5053 Diag(SR.getBegin(), diag::err_template_arg_must_be_expr) << SR;
5054 Diag(Param->getLocation(), diag::note_template_param_here);
5058 case TemplateArgument::Pack:
5059 llvm_unreachable("Caller must expand template argument packs");
5066 // Check template template parameters.
5067 TemplateTemplateParmDecl *TempParm = cast<TemplateTemplateParmDecl>(Param);
5069 TemplateParameterList *Params = TempParm->getTemplateParameters();
5070 if (TempParm->isExpandedParameterPack())
5071 Params = TempParm->getExpansionTemplateParameters(ArgumentPackIndex);
5073 // Substitute into the template parameter list of the template
5074 // template parameter, since previously-supplied template arguments
5075 // may appear within the template template parameter.
5077 // FIXME: Skip this if the parameters aren't instantiation-dependent.
5079 // Set up a template instantiation context.
5080 LocalInstantiationScope Scope(*this);
5081 InstantiatingTemplate Inst(*this, TemplateLoc, Template,
5082 TempParm, Converted,
5083 SourceRange(TemplateLoc, RAngleLoc));
5084 if (Inst.isInvalid())
5087 TemplateArgumentList TemplateArgs(TemplateArgumentList::OnStack, Converted);
5088 Params = SubstTemplateParams(Params, CurContext,
5089 MultiLevelTemplateArgumentList(TemplateArgs));
5094 // C++1z [temp.local]p1: (DR1004)
5095 // When [the injected-class-name] is used [...] as a template-argument for
5096 // a template template-parameter [...] it refers to the class template
5098 if (Arg.getArgument().getKind() == TemplateArgument::Type) {
5099 TemplateArgumentLoc ConvertedArg = convertTypeTemplateArgumentToTemplate(
5100 Arg.getTypeSourceInfo()->getTypeLoc());
5101 if (!ConvertedArg.getArgument().isNull())
5105 switch (Arg.getArgument().getKind()) {
5106 case TemplateArgument::Null:
5107 llvm_unreachable("Should never see a NULL template argument here");
5109 case TemplateArgument::Template:
5110 case TemplateArgument::TemplateExpansion:
5111 if (CheckTemplateTemplateArgument(Params, Arg))
5114 Converted.push_back(Arg.getArgument());
5117 case TemplateArgument::Expression:
5118 case TemplateArgument::Type:
5119 // We have a template template parameter but the template
5120 // argument does not refer to a template.
5121 Diag(Arg.getLocation(), diag::err_template_arg_must_be_template)
5122 << getLangOpts().CPlusPlus11;
5125 case TemplateArgument::Declaration:
5126 llvm_unreachable("Declaration argument with template template parameter");
5127 case TemplateArgument::Integral:
5128 llvm_unreachable("Integral argument with template template parameter");
5129 case TemplateArgument::NullPtr:
5130 llvm_unreachable("Null pointer argument with template template parameter");
5132 case TemplateArgument::Pack:
5133 llvm_unreachable("Caller must expand template argument packs");
5139 /// Check whether the template parameter is a pack expansion, and if so,
5140 /// determine the number of parameters produced by that expansion. For instance:
5143 /// template<typename ...Ts> struct A {
5144 /// template<Ts ...NTs, template<Ts> class ...TTs, typename ...Us> struct B;
5148 /// In \c A<int,int>::B, \c NTs and \c TTs have expanded pack size 2, and \c Us
5149 /// is not a pack expansion, so returns an empty Optional.
5150 static Optional<unsigned> getExpandedPackSize(NamedDecl *Param) {
5151 if (NonTypeTemplateParmDecl *NTTP
5152 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
5153 if (NTTP->isExpandedParameterPack())
5154 return NTTP->getNumExpansionTypes();
5157 if (TemplateTemplateParmDecl *TTP
5158 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
5159 if (TTP->isExpandedParameterPack())
5160 return TTP->getNumExpansionTemplateParameters();
5166 /// Diagnose a missing template argument.
5167 template<typename TemplateParmDecl>
5168 static bool diagnoseMissingArgument(Sema &S, SourceLocation Loc,
5170 const TemplateParmDecl *D,
5171 TemplateArgumentListInfo &Args) {
5172 // Dig out the most recent declaration of the template parameter; there may be
5173 // declarations of the template that are more recent than TD.
5174 D = cast<TemplateParmDecl>(cast<TemplateDecl>(TD->getMostRecentDecl())
5175 ->getTemplateParameters()
5176 ->getParam(D->getIndex()));
5178 // If there's a default argument that's not visible, diagnose that we're
5179 // missing a module import.
5180 llvm::SmallVector<Module*, 8> Modules;
5181 if (D->hasDefaultArgument() && !S.hasVisibleDefaultArgument(D, &Modules)) {
5182 S.diagnoseMissingImport(Loc, cast<NamedDecl>(TD),
5183 D->getDefaultArgumentLoc(), Modules,
5184 Sema::MissingImportKind::DefaultArgument,
5189 // FIXME: If there's a more recent default argument that *is* visible,
5190 // diagnose that it was declared too late.
5192 TemplateParameterList *Params = TD->getTemplateParameters();
5194 S.Diag(Loc, diag::err_template_arg_list_different_arity)
5195 << /*not enough args*/0
5196 << (int)S.getTemplateNameKindForDiagnostics(TemplateName(TD))
5198 S.Diag(TD->getLocation(), diag::note_template_decl_here)
5199 << Params->getSourceRange();
5203 /// Check that the given template argument list is well-formed
5204 /// for specializing the given template.
5205 bool Sema::CheckTemplateArgumentList(
5206 TemplateDecl *Template, SourceLocation TemplateLoc,
5207 TemplateArgumentListInfo &TemplateArgs, bool PartialTemplateArgs,
5208 SmallVectorImpl<TemplateArgument> &Converted,
5209 bool UpdateArgsWithConversions) {
5210 // Make a copy of the template arguments for processing. Only make the
5211 // changes at the end when successful in matching the arguments to the
5213 TemplateArgumentListInfo NewArgs = TemplateArgs;
5215 // Make sure we get the template parameter list from the most
5216 // recentdeclaration, since that is the only one that has is guaranteed to
5217 // have all the default template argument information.
5218 TemplateParameterList *Params =
5219 cast<TemplateDecl>(Template->getMostRecentDecl())
5220 ->getTemplateParameters();
5222 SourceLocation RAngleLoc = NewArgs.getRAngleLoc();
5224 // C++ [temp.arg]p1:
5225 // [...] The type and form of each template-argument specified in
5226 // a template-id shall match the type and form specified for the
5227 // corresponding parameter declared by the template in its
5228 // template-parameter-list.
5229 bool isTemplateTemplateParameter = isa<TemplateTemplateParmDecl>(Template);
5230 SmallVector<TemplateArgument, 2> ArgumentPack;
5231 unsigned ArgIdx = 0, NumArgs = NewArgs.size();
5232 LocalInstantiationScope InstScope(*this, true);
5233 for (TemplateParameterList::iterator Param = Params->begin(),
5234 ParamEnd = Params->end();
5235 Param != ParamEnd; /* increment in loop */) {
5236 // If we have an expanded parameter pack, make sure we don't have too
5238 if (Optional<unsigned> Expansions = getExpandedPackSize(*Param)) {
5239 if (*Expansions == ArgumentPack.size()) {
5240 // We're done with this parameter pack. Pack up its arguments and add
5241 // them to the list.
5242 Converted.push_back(
5243 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5244 ArgumentPack.clear();
5246 // This argument is assigned to the next parameter.
5249 } else if (ArgIdx == NumArgs && !PartialTemplateArgs) {
5250 // Not enough arguments for this parameter pack.
5251 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5252 << /*not enough args*/0
5253 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5255 Diag(Template->getLocation(), diag::note_template_decl_here)
5256 << Params->getSourceRange();
5261 if (ArgIdx < NumArgs) {
5262 // Check the template argument we were given.
5263 if (CheckTemplateArgument(*Param, NewArgs[ArgIdx], Template,
5264 TemplateLoc, RAngleLoc,
5265 ArgumentPack.size(), Converted))
5268 bool PackExpansionIntoNonPack =
5269 NewArgs[ArgIdx].getArgument().isPackExpansion() &&
5270 (!(*Param)->isTemplateParameterPack() || getExpandedPackSize(*Param));
5271 if (PackExpansionIntoNonPack && isa<TypeAliasTemplateDecl>(Template)) {
5272 // Core issue 1430: we have a pack expansion as an argument to an
5273 // alias template, and it's not part of a parameter pack. This
5274 // can't be canonicalized, so reject it now.
5275 Diag(NewArgs[ArgIdx].getLocation(),
5276 diag::err_alias_template_expansion_into_fixed_list)
5277 << NewArgs[ArgIdx].getSourceRange();
5278 Diag((*Param)->getLocation(), diag::note_template_param_here);
5282 // We're now done with this argument.
5285 if ((*Param)->isTemplateParameterPack()) {
5286 // The template parameter was a template parameter pack, so take the
5287 // deduced argument and place it on the argument pack. Note that we
5288 // stay on the same template parameter so that we can deduce more
5290 ArgumentPack.push_back(Converted.pop_back_val());
5292 // Move to the next template parameter.
5296 // If we just saw a pack expansion into a non-pack, then directly convert
5297 // the remaining arguments, because we don't know what parameters they'll
5299 if (PackExpansionIntoNonPack) {
5300 if (!ArgumentPack.empty()) {
5301 // If we were part way through filling in an expanded parameter pack,
5302 // fall back to just producing individual arguments.
5303 Converted.insert(Converted.end(),
5304 ArgumentPack.begin(), ArgumentPack.end());
5305 ArgumentPack.clear();
5308 while (ArgIdx < NumArgs) {
5309 Converted.push_back(NewArgs[ArgIdx].getArgument());
5319 // If we're checking a partial template argument list, we're done.
5320 if (PartialTemplateArgs) {
5321 if ((*Param)->isTemplateParameterPack() && !ArgumentPack.empty())
5322 Converted.push_back(
5323 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5328 // If we have a template parameter pack with no more corresponding
5329 // arguments, just break out now and we'll fill in the argument pack below.
5330 if ((*Param)->isTemplateParameterPack()) {
5331 assert(!getExpandedPackSize(*Param) &&
5332 "Should have dealt with this already");
5334 // A non-expanded parameter pack before the end of the parameter list
5335 // only occurs for an ill-formed template parameter list, unless we've
5336 // got a partial argument list for a function template, so just bail out.
5337 if (Param + 1 != ParamEnd)
5340 Converted.push_back(
5341 TemplateArgument::CreatePackCopy(Context, ArgumentPack));
5342 ArgumentPack.clear();
5348 // Check whether we have a default argument.
5349 TemplateArgumentLoc Arg;
5351 // Retrieve the default template argument from the template
5352 // parameter. For each kind of template parameter, we substitute the
5353 // template arguments provided thus far and any "outer" template arguments
5354 // (when the template parameter was part of a nested template) into
5355 // the default argument.
5356 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(*Param)) {
5357 if (!hasVisibleDefaultArgument(TTP))
5358 return diagnoseMissingArgument(*this, TemplateLoc, Template, TTP,
5361 TypeSourceInfo *ArgType = SubstDefaultTemplateArgument(*this,
5370 Arg = TemplateArgumentLoc(TemplateArgument(ArgType->getType()),
5372 } else if (NonTypeTemplateParmDecl *NTTP
5373 = dyn_cast<NonTypeTemplateParmDecl>(*Param)) {
5374 if (!hasVisibleDefaultArgument(NTTP))
5375 return diagnoseMissingArgument(*this, TemplateLoc, Template, NTTP,
5378 ExprResult E = SubstDefaultTemplateArgument(*this, Template,
5386 Expr *Ex = E.getAs<Expr>();
5387 Arg = TemplateArgumentLoc(TemplateArgument(Ex), Ex);
5389 TemplateTemplateParmDecl *TempParm
5390 = cast<TemplateTemplateParmDecl>(*Param);
5392 if (!hasVisibleDefaultArgument(TempParm))
5393 return diagnoseMissingArgument(*this, TemplateLoc, Template, TempParm,
5396 NestedNameSpecifierLoc QualifierLoc;
5397 TemplateName Name = SubstDefaultTemplateArgument(*this, Template,
5406 Arg = TemplateArgumentLoc(TemplateArgument(Name), QualifierLoc,
5407 TempParm->getDefaultArgument().getTemplateNameLoc());
5410 // Introduce an instantiation record that describes where we are using
5411 // the default template argument. We're not actually instantiating a
5412 // template here, we just create this object to put a note into the
5414 InstantiatingTemplate Inst(*this, RAngleLoc, Template, *Param, Converted,
5415 SourceRange(TemplateLoc, RAngleLoc));
5416 if (Inst.isInvalid())
5419 // Check the default template argument.
5420 if (CheckTemplateArgument(*Param, Arg, Template, TemplateLoc,
5421 RAngleLoc, 0, Converted))
5424 // Core issue 150 (assumed resolution): if this is a template template
5425 // parameter, keep track of the default template arguments from the
5426 // template definition.
5427 if (isTemplateTemplateParameter)
5428 NewArgs.addArgument(Arg);
5430 // Move to the next template parameter and argument.
5435 // If we're performing a partial argument substitution, allow any trailing
5436 // pack expansions; they might be empty. This can happen even if
5437 // PartialTemplateArgs is false (the list of arguments is complete but
5438 // still dependent).
5439 if (ArgIdx < NumArgs && CurrentInstantiationScope &&
5440 CurrentInstantiationScope->getPartiallySubstitutedPack()) {
5441 while (ArgIdx < NumArgs && NewArgs[ArgIdx].getArgument().isPackExpansion())
5442 Converted.push_back(NewArgs[ArgIdx++].getArgument());
5445 // If we have any leftover arguments, then there were too many arguments.
5446 // Complain and fail.
5447 if (ArgIdx < NumArgs) {
5448 Diag(TemplateLoc, diag::err_template_arg_list_different_arity)
5449 << /*too many args*/1
5450 << (int)getTemplateNameKindForDiagnostics(TemplateName(Template))
5452 << SourceRange(NewArgs[ArgIdx].getLocation(), NewArgs.getRAngleLoc());
5453 Diag(Template->getLocation(), diag::note_template_decl_here)
5454 << Params->getSourceRange();
5458 // No problems found with the new argument list, propagate changes back
5460 if (UpdateArgsWithConversions)
5461 TemplateArgs = std::move(NewArgs);
5467 class UnnamedLocalNoLinkageFinder
5468 : public TypeVisitor<UnnamedLocalNoLinkageFinder, bool>
5473 typedef TypeVisitor<UnnamedLocalNoLinkageFinder, bool> inherited;
5476 UnnamedLocalNoLinkageFinder(Sema &S, SourceRange SR) : S(S), SR(SR) { }
5478 bool Visit(QualType T) {
5479 return T.isNull() ? false : inherited::Visit(T.getTypePtr());
5482 #define TYPE(Class, Parent) \
5483 bool Visit##Class##Type(const Class##Type *);
5484 #define ABSTRACT_TYPE(Class, Parent) \
5485 bool Visit##Class##Type(const Class##Type *) { return false; }
5486 #define NON_CANONICAL_TYPE(Class, Parent) \
5487 bool Visit##Class##Type(const Class##Type *) { return false; }
5488 #include "clang/AST/TypeNodes.inc"
5490 bool VisitTagDecl(const TagDecl *Tag);
5491 bool VisitNestedNameSpecifier(NestedNameSpecifier *NNS);
5493 } // end anonymous namespace
5495 bool UnnamedLocalNoLinkageFinder::VisitBuiltinType(const BuiltinType*) {
5499 bool UnnamedLocalNoLinkageFinder::VisitComplexType(const ComplexType* T) {
5500 return Visit(T->getElementType());
5503 bool UnnamedLocalNoLinkageFinder::VisitPointerType(const PointerType* T) {
5504 return Visit(T->getPointeeType());
5507 bool UnnamedLocalNoLinkageFinder::VisitBlockPointerType(
5508 const BlockPointerType* T) {
5509 return Visit(T->getPointeeType());
5512 bool UnnamedLocalNoLinkageFinder::VisitLValueReferenceType(
5513 const LValueReferenceType* T) {
5514 return Visit(T->getPointeeType());
5517 bool UnnamedLocalNoLinkageFinder::VisitRValueReferenceType(
5518 const RValueReferenceType* T) {
5519 return Visit(T->getPointeeType());
5522 bool UnnamedLocalNoLinkageFinder::VisitMemberPointerType(
5523 const MemberPointerType* T) {
5524 return Visit(T->getPointeeType()) || Visit(QualType(T->getClass(), 0));
5527 bool UnnamedLocalNoLinkageFinder::VisitConstantArrayType(
5528 const ConstantArrayType* T) {
5529 return Visit(T->getElementType());
5532 bool UnnamedLocalNoLinkageFinder::VisitIncompleteArrayType(
5533 const IncompleteArrayType* T) {
5534 return Visit(T->getElementType());
5537 bool UnnamedLocalNoLinkageFinder::VisitVariableArrayType(
5538 const VariableArrayType* T) {
5539 return Visit(T->getElementType());
5542 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedArrayType(
5543 const DependentSizedArrayType* T) {
5544 return Visit(T->getElementType());
5547 bool UnnamedLocalNoLinkageFinder::VisitDependentSizedExtVectorType(
5548 const DependentSizedExtVectorType* T) {
5549 return Visit(T->getElementType());
5552 bool UnnamedLocalNoLinkageFinder::VisitDependentAddressSpaceType(
5553 const DependentAddressSpaceType *T) {
5554 return Visit(T->getPointeeType());
5557 bool UnnamedLocalNoLinkageFinder::VisitVectorType(const VectorType* T) {
5558 return Visit(T->getElementType());
5561 bool UnnamedLocalNoLinkageFinder::VisitDependentVectorType(
5562 const DependentVectorType *T) {
5563 return Visit(T->getElementType());
5566 bool UnnamedLocalNoLinkageFinder::VisitExtVectorType(const ExtVectorType* T) {
5567 return Visit(T->getElementType());
5570 bool UnnamedLocalNoLinkageFinder::VisitFunctionProtoType(
5571 const FunctionProtoType* T) {
5572 for (const auto &A : T->param_types()) {
5577 return Visit(T->getReturnType());
5580 bool UnnamedLocalNoLinkageFinder::VisitFunctionNoProtoType(
5581 const FunctionNoProtoType* T) {
5582 return Visit(T->getReturnType());
5585 bool UnnamedLocalNoLinkageFinder::VisitUnresolvedUsingType(
5586 const UnresolvedUsingType*) {
5590 bool UnnamedLocalNoLinkageFinder::VisitTypeOfExprType(const TypeOfExprType*) {
5594 bool UnnamedLocalNoLinkageFinder::VisitTypeOfType(const TypeOfType* T) {
5595 return Visit(T->getUnderlyingType());
5598 bool UnnamedLocalNoLinkageFinder::VisitDecltypeType(const DecltypeType*) {
5602 bool UnnamedLocalNoLinkageFinder::VisitUnaryTransformType(
5603 const UnaryTransformType*) {
5607 bool UnnamedLocalNoLinkageFinder::VisitAutoType(const AutoType *T) {
5608 return Visit(T->getDeducedType());
5611 bool UnnamedLocalNoLinkageFinder::VisitDeducedTemplateSpecializationType(
5612 const DeducedTemplateSpecializationType *T) {
5613 return Visit(T->getDeducedType());
5616 bool UnnamedLocalNoLinkageFinder::VisitRecordType(const RecordType* T) {
5617 return VisitTagDecl(T->getDecl());
5620 bool UnnamedLocalNoLinkageFinder::VisitEnumType(const EnumType* T) {
5621 return VisitTagDecl(T->getDecl());
5624 bool UnnamedLocalNoLinkageFinder::VisitTemplateTypeParmType(
5625 const TemplateTypeParmType*) {
5629 bool UnnamedLocalNoLinkageFinder::VisitSubstTemplateTypeParmPackType(
5630 const SubstTemplateTypeParmPackType *) {
5634 bool UnnamedLocalNoLinkageFinder::VisitTemplateSpecializationType(
5635 const TemplateSpecializationType*) {
5639 bool UnnamedLocalNoLinkageFinder::VisitInjectedClassNameType(
5640 const InjectedClassNameType* T) {
5641 return VisitTagDecl(T->getDecl());
5644 bool UnnamedLocalNoLinkageFinder::VisitDependentNameType(
5645 const DependentNameType* T) {
5646 return VisitNestedNameSpecifier(T->getQualifier());
5649 bool UnnamedLocalNoLinkageFinder::VisitDependentTemplateSpecializationType(
5650 const DependentTemplateSpecializationType* T) {
5651 return VisitNestedNameSpecifier(T->getQualifier());
5654 bool UnnamedLocalNoLinkageFinder::VisitPackExpansionType(
5655 const PackExpansionType* T) {
5656 return Visit(T->getPattern());
5659 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectType(const ObjCObjectType *) {
5663 bool UnnamedLocalNoLinkageFinder::VisitObjCInterfaceType(
5664 const ObjCInterfaceType *) {
5668 bool UnnamedLocalNoLinkageFinder::VisitObjCObjectPointerType(
5669 const ObjCObjectPointerType *) {
5673 bool UnnamedLocalNoLinkageFinder::VisitAtomicType(const AtomicType* T) {
5674 return Visit(T->getValueType());
5677 bool UnnamedLocalNoLinkageFinder::VisitPipeType(const PipeType* T) {
5681 bool UnnamedLocalNoLinkageFinder::VisitTagDecl(const TagDecl *Tag) {
5682 if (Tag->getDeclContext()->isFunctionOrMethod()) {
5683 S.Diag(SR.getBegin(),
5684 S.getLangOpts().CPlusPlus11 ?
5685 diag::warn_cxx98_compat_template_arg_local_type :
5686 diag::ext_template_arg_local_type)
5687 << S.Context.getTypeDeclType(Tag) << SR;
5691 if (!Tag->hasNameForLinkage()) {
5692 S.Diag(SR.getBegin(),
5693 S.getLangOpts().CPlusPlus11 ?
5694 diag::warn_cxx98_compat_template_arg_unnamed_type :
5695 diag::ext_template_arg_unnamed_type) << SR;
5696 S.Diag(Tag->getLocation(), diag::note_template_unnamed_type_here);
5703 bool UnnamedLocalNoLinkageFinder::VisitNestedNameSpecifier(
5704 NestedNameSpecifier *NNS) {
5705 if (NNS->getPrefix() && VisitNestedNameSpecifier(NNS->getPrefix()))
5708 switch (NNS->getKind()) {
5709 case NestedNameSpecifier::Identifier:
5710 case NestedNameSpecifier::Namespace:
5711 case NestedNameSpecifier::NamespaceAlias:
5712 case NestedNameSpecifier::Global:
5713 case NestedNameSpecifier::Super:
5716 case NestedNameSpecifier::TypeSpec:
5717 case NestedNameSpecifier::TypeSpecWithTemplate:
5718 return Visit(QualType(NNS->getAsType(), 0));
5720 llvm_unreachable("Invalid NestedNameSpecifier::Kind!");
5723 /// Check a template argument against its corresponding
5724 /// template type parameter.
5726 /// This routine implements the semantics of C++ [temp.arg.type]. It
5727 /// returns true if an error occurred, and false otherwise.
5728 bool Sema::CheckTemplateArgument(TemplateTypeParmDecl *Param,
5729 TypeSourceInfo *ArgInfo) {
5730 assert(ArgInfo && "invalid TypeSourceInfo");
5731 QualType Arg = ArgInfo->getType();
5732 SourceRange SR = ArgInfo->getTypeLoc().getSourceRange();
5734 if (Arg->isVariablyModifiedType()) {
5735 return Diag(SR.getBegin(), diag::err_variably_modified_template_arg) << Arg;
5736 } else if (Context.hasSameUnqualifiedType(Arg, Context.OverloadTy)) {
5737 return Diag(SR.getBegin(), diag::err_template_arg_overload_type) << SR;
5740 // C++03 [temp.arg.type]p2:
5741 // A local type, a type with no linkage, an unnamed type or a type
5742 // compounded from any of these types shall not be used as a
5743 // template-argument for a template type-parameter.
5745 // C++11 allows these, and even in C++03 we allow them as an extension with
5747 if (LangOpts.CPlusPlus11 || Arg->hasUnnamedOrLocalType()) {
5748 UnnamedLocalNoLinkageFinder Finder(*this, SR);
5749 (void)Finder.Visit(Context.getCanonicalType(Arg));
5755 enum NullPointerValueKind {
5761 /// Determine whether the given template argument is a null pointer
5762 /// value of the appropriate type.
5763 static NullPointerValueKind
5764 isNullPointerValueTemplateArgument(Sema &S, NonTypeTemplateParmDecl *Param,
5765 QualType ParamType, Expr *Arg,
5766 Decl *Entity = nullptr) {
5767 if (Arg->isValueDependent() || Arg->isTypeDependent())
5768 return NPV_NotNullPointer;
5770 // dllimport'd entities aren't constant but are available inside of template
5772 if (Entity && Entity->hasAttr<DLLImportAttr>())
5773 return NPV_NotNullPointer;
5775 if (!S.isCompleteType(Arg->getExprLoc(), ParamType))
5777 "Incomplete parameter type in isNullPointerValueTemplateArgument!");
5779 if (!S.getLangOpts().CPlusPlus11)
5780 return NPV_NotNullPointer;
5782 // Determine whether we have a constant expression.
5783 ExprResult ArgRV = S.DefaultFunctionArrayConversion(Arg);
5784 if (ArgRV.isInvalid())
5788 Expr::EvalResult EvalResult;
5789 SmallVector<PartialDiagnosticAt, 8> Notes;
5790 EvalResult.Diag = &Notes;
5791 if (!Arg->EvaluateAsRValue(EvalResult, S.Context) ||
5792 EvalResult.HasSideEffects) {
5793 SourceLocation DiagLoc = Arg->getExprLoc();
5795 // If our only note is the usual "invalid subexpression" note, just point
5796 // the caret at its location rather than producing an essentially
5798 if (Notes.size() == 1 && Notes[0].second.getDiagID() ==
5799 diag::note_invalid_subexpr_in_const_expr) {
5800 DiagLoc = Notes[0].first;
5804 S.Diag(DiagLoc, diag::err_template_arg_not_address_constant)
5805 << Arg->getType() << Arg->getSourceRange();
5806 for (unsigned I = 0, N = Notes.size(); I != N; ++I)
5807 S.Diag(Notes[I].first, Notes[I].second);
5809 S.Diag(Param->getLocation(), diag::note_template_param_here);
5813 // C++11 [temp.arg.nontype]p1:
5814 // - an address constant expression of type std::nullptr_t
5815 if (Arg->getType()->isNullPtrType())
5816 return NPV_NullPointer;
5818 // - a constant expression that evaluates to a null pointer value (4.10); or
5819 // - a constant expression that evaluates to a null member pointer value
5821 if ((EvalResult.Val.isLValue() && !EvalResult.Val.getLValueBase()) ||
5822 (EvalResult.Val.isMemberPointer() &&
5823 !EvalResult.Val.getMemberPointerDecl())) {
5824 // If our expression has an appropriate type, we've succeeded.
5825 bool ObjCLifetimeConversion;
5826 if (S.Context.hasSameUnqualifiedType(Arg->getType(), ParamType) ||
5827 S.IsQualificationConversion(Arg->getType(), ParamType, false,
5828 ObjCLifetimeConversion))
5829 return NPV_NullPointer;
5831 // The types didn't match, but we know we got a null pointer; complain,
5832 // then recover as if the types were correct.
5833 S.Diag(Arg->getExprLoc(), diag::err_template_arg_wrongtype_null_constant)
5834 << Arg->getType() << ParamType << Arg->getSourceRange();
5835 S.Diag(Param->getLocation(), diag::note_template_param_here);
5836 return NPV_NullPointer;
5839 // If we don't have a null pointer value, but we do have a NULL pointer
5840 // constant, suggest a cast to the appropriate type.
5841 if (Arg->isNullPointerConstant(S.Context, Expr::NPC_NeverValueDependent)) {
5842 std::string Code = "static_cast<" + ParamType.getAsString() + ">(";
5843 S.Diag(Arg->getExprLoc(), diag::err_template_arg_untyped_null_constant)
5844 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), Code)
5845 << FixItHint::CreateInsertion(S.getLocForEndOfToken(Arg->getEndLoc()),
5847 S.Diag(Param->getLocation(), diag::note_template_param_here);
5848 return NPV_NullPointer;
5851 // FIXME: If we ever want to support general, address-constant expressions
5852 // as non-type template arguments, we should return the ExprResult here to
5853 // be interpreted by the caller.
5854 return NPV_NotNullPointer;
5857 /// Checks whether the given template argument is compatible with its
5858 /// template parameter.
5859 static bool CheckTemplateArgumentIsCompatibleWithParameter(
5860 Sema &S, NonTypeTemplateParmDecl *Param, QualType ParamType, Expr *ArgIn,
5861 Expr *Arg, QualType ArgType) {
5862 bool ObjCLifetimeConversion;
5863 if (ParamType->isPointerType() &&
5864 !ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType() &&
5865 S.IsQualificationConversion(ArgType, ParamType, false,
5866 ObjCLifetimeConversion)) {
5867 // For pointer-to-object types, qualification conversions are
5870 if (const ReferenceType *ParamRef = ParamType->getAs<ReferenceType>()) {
5871 if (!ParamRef->getPointeeType()->isFunctionType()) {
5872 // C++ [temp.arg.nontype]p5b3:
5873 // For a non-type template-parameter of type reference to
5874 // object, no conversions apply. The type referred to by the
5875 // reference may be more cv-qualified than the (otherwise
5876 // identical) type of the template- argument. The
5877 // template-parameter is bound directly to the
5878 // template-argument, which shall be an lvalue.
5880 // FIXME: Other qualifiers?
5881 unsigned ParamQuals = ParamRef->getPointeeType().getCVRQualifiers();
5882 unsigned ArgQuals = ArgType.getCVRQualifiers();
5884 if ((ParamQuals | ArgQuals) != ParamQuals) {
5885 S.Diag(Arg->getBeginLoc(),
5886 diag::err_template_arg_ref_bind_ignores_quals)
5887 << ParamType << Arg->getType() << Arg->getSourceRange();
5888 S.Diag(Param->getLocation(), diag::note_template_param_here);
5894 // At this point, the template argument refers to an object or
5895 // function with external linkage. We now need to check whether the
5896 // argument and parameter types are compatible.
5897 if (!S.Context.hasSameUnqualifiedType(ArgType,
5898 ParamType.getNonReferenceType())) {
5899 // We can't perform this conversion or binding.
5900 if (ParamType->isReferenceType())
5901 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_no_ref_bind)
5902 << ParamType << ArgIn->getType() << Arg->getSourceRange();
5904 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
5905 << ArgIn->getType() << ParamType << Arg->getSourceRange();
5906 S.Diag(Param->getLocation(), diag::note_template_param_here);
5914 /// Checks whether the given template argument is the address
5915 /// of an object or function according to C++ [temp.arg.nontype]p1.
5917 CheckTemplateArgumentAddressOfObjectOrFunction(Sema &S,
5918 NonTypeTemplateParmDecl *Param,
5921 TemplateArgument &Converted) {
5922 bool Invalid = false;
5924 QualType ArgType = Arg->getType();
5926 bool AddressTaken = false;
5927 SourceLocation AddrOpLoc;
5928 if (S.getLangOpts().MicrosoftExt) {
5929 // Microsoft Visual C++ strips all casts, allows an arbitrary number of
5930 // dereference and address-of operators.
5931 Arg = Arg->IgnoreParenCasts();
5933 bool ExtWarnMSTemplateArg = false;
5934 UnaryOperatorKind FirstOpKind;
5935 SourceLocation FirstOpLoc;
5936 while (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
5937 UnaryOperatorKind UnOpKind = UnOp->getOpcode();
5938 if (UnOpKind == UO_Deref)
5939 ExtWarnMSTemplateArg = true;
5940 if (UnOpKind == UO_AddrOf || UnOpKind == UO_Deref) {
5941 Arg = UnOp->getSubExpr()->IgnoreParenCasts();
5942 if (!AddrOpLoc.isValid()) {
5943 FirstOpKind = UnOpKind;
5944 FirstOpLoc = UnOp->getOperatorLoc();
5949 if (FirstOpLoc.isValid()) {
5950 if (ExtWarnMSTemplateArg)
5951 S.Diag(ArgIn->getBeginLoc(), diag::ext_ms_deref_template_argument)
5952 << ArgIn->getSourceRange();
5954 if (FirstOpKind == UO_AddrOf)
5955 AddressTaken = true;
5956 else if (Arg->getType()->isPointerType()) {
5957 // We cannot let pointers get dereferenced here, that is obviously not a
5958 // constant expression.
5959 assert(FirstOpKind == UO_Deref);
5960 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
5961 << Arg->getSourceRange();
5965 // See through any implicit casts we added to fix the type.
5966 Arg = Arg->IgnoreImpCasts();
5968 // C++ [temp.arg.nontype]p1:
5970 // A template-argument for a non-type, non-template
5971 // template-parameter shall be one of: [...]
5973 // -- the address of an object or function with external
5974 // linkage, including function templates and function
5975 // template-ids but excluding non-static class members,
5976 // expressed as & id-expression where the & is optional if
5977 // the name refers to a function or array, or if the
5978 // corresponding template-parameter is a reference; or
5980 // In C++98/03 mode, give an extension warning on any extra parentheses.
5981 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
5982 bool ExtraParens = false;
5983 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
5984 if (!Invalid && !ExtraParens) {
5985 S.Diag(Arg->getBeginLoc(),
5986 S.getLangOpts().CPlusPlus11
5987 ? diag::warn_cxx98_compat_template_arg_extra_parens
5988 : diag::ext_template_arg_extra_parens)
5989 << Arg->getSourceRange();
5993 Arg = Parens->getSubExpr();
5996 while (SubstNonTypeTemplateParmExpr *subst =
5997 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
5998 Arg = subst->getReplacement()->IgnoreImpCasts();
6000 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6001 if (UnOp->getOpcode() == UO_AddrOf) {
6002 Arg = UnOp->getSubExpr();
6003 AddressTaken = true;
6004 AddrOpLoc = UnOp->getOperatorLoc();
6008 while (SubstNonTypeTemplateParmExpr *subst =
6009 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6010 Arg = subst->getReplacement()->IgnoreImpCasts();
6013 DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(Arg);
6014 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6016 // If our parameter has pointer type, check for a null template value.
6017 if (ParamType->isPointerType() || ParamType->isNullPtrType()) {
6018 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ArgIn,
6020 case NPV_NullPointer:
6021 S.Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6022 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6023 /*isNullPtr=*/true);
6029 case NPV_NotNullPointer:
6034 // Stop checking the precise nature of the argument if it is value dependent,
6035 // it should be checked when instantiated.
6036 if (Arg->isValueDependent()) {
6037 Converted = TemplateArgument(ArgIn);
6041 if (isa<CXXUuidofExpr>(Arg)) {
6042 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType,
6043 ArgIn, Arg, ArgType))
6046 Converted = TemplateArgument(ArgIn);
6051 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6052 << Arg->getSourceRange();
6053 S.Diag(Param->getLocation(), diag::note_template_param_here);
6057 // Cannot refer to non-static data members
6058 if (isa<FieldDecl>(Entity) || isa<IndirectFieldDecl>(Entity)) {
6059 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_field)
6060 << Entity << Arg->getSourceRange();
6061 S.Diag(Param->getLocation(), diag::note_template_param_here);
6065 // Cannot refer to non-static member functions
6066 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Entity)) {
6067 if (!Method->isStatic()) {
6068 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_method)
6069 << Method << Arg->getSourceRange();
6070 S.Diag(Param->getLocation(), diag::note_template_param_here);
6075 FunctionDecl *Func = dyn_cast<FunctionDecl>(Entity);
6076 VarDecl *Var = dyn_cast<VarDecl>(Entity);
6078 // A non-type template argument must refer to an object or function.
6079 if (!Func && !Var) {
6080 // We found something, but we don't know specifically what it is.
6081 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_object_or_func)
6082 << Arg->getSourceRange();
6083 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6087 // Address / reference template args must have external linkage in C++98.
6088 if (Entity->getFormalLinkage() == InternalLinkage) {
6089 S.Diag(Arg->getBeginLoc(),
6090 S.getLangOpts().CPlusPlus11
6091 ? diag::warn_cxx98_compat_template_arg_object_internal
6092 : diag::ext_template_arg_object_internal)
6093 << !Func << Entity << Arg->getSourceRange();
6094 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6096 } else if (!Entity->hasLinkage()) {
6097 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_object_no_linkage)
6098 << !Func << Entity << Arg->getSourceRange();
6099 S.Diag(Entity->getLocation(), diag::note_template_arg_internal_object)
6105 // If the template parameter has pointer type, the function decays.
6106 if (ParamType->isPointerType() && !AddressTaken)
6107 ArgType = S.Context.getPointerType(Func->getType());
6108 else if (AddressTaken && ParamType->isReferenceType()) {
6109 // If we originally had an address-of operator, but the
6110 // parameter has reference type, complain and (if things look
6111 // like they will work) drop the address-of operator.
6112 if (!S.Context.hasSameUnqualifiedType(Func->getType(),
6113 ParamType.getNonReferenceType())) {
6114 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6116 S.Diag(Param->getLocation(), diag::note_template_param_here);
6120 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6122 << FixItHint::CreateRemoval(AddrOpLoc);
6123 S.Diag(Param->getLocation(), diag::note_template_param_here);
6125 ArgType = Func->getType();
6128 // A value of reference type is not an object.
6129 if (Var->getType()->isReferenceType()) {
6130 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_reference_var)
6131 << Var->getType() << Arg->getSourceRange();
6132 S.Diag(Param->getLocation(), diag::note_template_param_here);
6136 // A template argument must have static storage duration.
6137 if (Var->getTLSKind()) {
6138 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_thread_local)
6139 << Arg->getSourceRange();
6140 S.Diag(Var->getLocation(), diag::note_template_arg_refers_here);
6144 // If the template parameter has pointer type, we must have taken
6145 // the address of this object.
6146 if (ParamType->isReferenceType()) {
6148 // If we originally had an address-of operator, but the
6149 // parameter has reference type, complain and (if things look
6150 // like they will work) drop the address-of operator.
6151 if (!S.Context.hasSameUnqualifiedType(Var->getType(),
6152 ParamType.getNonReferenceType())) {
6153 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6155 S.Diag(Param->getLocation(), diag::note_template_param_here);
6159 S.Diag(AddrOpLoc, diag::err_template_arg_address_of_non_pointer)
6161 << FixItHint::CreateRemoval(AddrOpLoc);
6162 S.Diag(Param->getLocation(), diag::note_template_param_here);
6164 ArgType = Var->getType();
6166 } else if (!AddressTaken && ParamType->isPointerType()) {
6167 if (Var->getType()->isArrayType()) {
6168 // Array-to-pointer decay.
6169 ArgType = S.Context.getArrayDecayedType(Var->getType());
6171 // If the template parameter has pointer type but the address of
6172 // this object was not taken, complain and (possibly) recover by
6173 // taking the address of the entity.
6174 ArgType = S.Context.getPointerType(Var->getType());
6175 if (!S.Context.hasSameUnqualifiedType(ArgType, ParamType)) {
6176 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6178 S.Diag(Param->getLocation(), diag::note_template_param_here);
6182 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_address_of)
6183 << ParamType << FixItHint::CreateInsertion(Arg->getBeginLoc(), "&");
6185 S.Diag(Param->getLocation(), diag::note_template_param_here);
6190 if (CheckTemplateArgumentIsCompatibleWithParameter(S, Param, ParamType, ArgIn,
6194 // Create the template argument.
6196 TemplateArgument(cast<ValueDecl>(Entity->getCanonicalDecl()), ParamType);
6197 S.MarkAnyDeclReferenced(Arg->getBeginLoc(), Entity, false);
6201 /// Checks whether the given template argument is a pointer to
6202 /// member constant according to C++ [temp.arg.nontype]p1.
6203 static bool CheckTemplateArgumentPointerToMember(Sema &S,
6204 NonTypeTemplateParmDecl *Param,
6207 TemplateArgument &Converted) {
6208 bool Invalid = false;
6210 Expr *Arg = ResultArg;
6211 bool ObjCLifetimeConversion;
6213 // C++ [temp.arg.nontype]p1:
6215 // A template-argument for a non-type, non-template
6216 // template-parameter shall be one of: [...]
6218 // -- a pointer to member expressed as described in 5.3.1.
6219 DeclRefExpr *DRE = nullptr;
6221 // In C++98/03 mode, give an extension warning on any extra parentheses.
6222 // See http://www.open-std.org/jtc1/sc22/wg21/docs/cwg_defects.html#773
6223 bool ExtraParens = false;
6224 while (ParenExpr *Parens = dyn_cast<ParenExpr>(Arg)) {
6225 if (!Invalid && !ExtraParens) {
6226 S.Diag(Arg->getBeginLoc(),
6227 S.getLangOpts().CPlusPlus11
6228 ? diag::warn_cxx98_compat_template_arg_extra_parens
6229 : diag::ext_template_arg_extra_parens)
6230 << Arg->getSourceRange();
6234 Arg = Parens->getSubExpr();
6237 while (SubstNonTypeTemplateParmExpr *subst =
6238 dyn_cast<SubstNonTypeTemplateParmExpr>(Arg))
6239 Arg = subst->getReplacement()->IgnoreImpCasts();
6241 // A pointer-to-member constant written &Class::member.
6242 if (UnaryOperator *UnOp = dyn_cast<UnaryOperator>(Arg)) {
6243 if (UnOp->getOpcode() == UO_AddrOf) {
6244 DRE = dyn_cast<DeclRefExpr>(UnOp->getSubExpr());
6245 if (DRE && !DRE->getQualifier())
6249 // A constant of pointer-to-member type.
6250 else if ((DRE = dyn_cast<DeclRefExpr>(Arg))) {
6251 ValueDecl *VD = DRE->getDecl();
6252 if (VD->getType()->isMemberPointerType()) {
6253 if (isa<NonTypeTemplateParmDecl>(VD)) {
6254 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6255 Converted = TemplateArgument(Arg);
6257 VD = cast<ValueDecl>(VD->getCanonicalDecl());
6258 Converted = TemplateArgument(VD, ParamType);
6267 ValueDecl *Entity = DRE ? DRE->getDecl() : nullptr;
6269 // Check for a null pointer value.
6270 switch (isNullPointerValueTemplateArgument(S, Param, ParamType, ResultArg,
6274 case NPV_NullPointer:
6275 S.Diag(ResultArg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6276 Converted = TemplateArgument(S.Context.getCanonicalType(ParamType),
6279 case NPV_NotNullPointer:
6283 if (S.IsQualificationConversion(ResultArg->getType(),
6284 ParamType.getNonReferenceType(), false,
6285 ObjCLifetimeConversion)) {
6286 ResultArg = S.ImpCastExprToType(ResultArg, ParamType, CK_NoOp,
6287 ResultArg->getValueKind())
6289 } else if (!S.Context.hasSameUnqualifiedType(
6290 ResultArg->getType(), ParamType.getNonReferenceType())) {
6291 // We can't perform this conversion.
6292 S.Diag(ResultArg->getBeginLoc(), diag::err_template_arg_not_convertible)
6293 << ResultArg->getType() << ParamType << ResultArg->getSourceRange();
6294 S.Diag(Param->getLocation(), diag::note_template_param_here);
6299 return S.Diag(Arg->getBeginLoc(),
6300 diag::err_template_arg_not_pointer_to_member_form)
6301 << Arg->getSourceRange();
6303 if (isa<FieldDecl>(DRE->getDecl()) ||
6304 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6305 isa<CXXMethodDecl>(DRE->getDecl())) {
6306 assert((isa<FieldDecl>(DRE->getDecl()) ||
6307 isa<IndirectFieldDecl>(DRE->getDecl()) ||
6308 !cast<CXXMethodDecl>(DRE->getDecl())->isStatic()) &&
6309 "Only non-static member pointers can make it here");
6311 // Okay: this is the address of a non-static member, and therefore
6312 // a member pointer constant.
6313 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6314 Converted = TemplateArgument(Arg);
6316 ValueDecl *D = cast<ValueDecl>(DRE->getDecl()->getCanonicalDecl());
6317 Converted = TemplateArgument(D, ParamType);
6322 // We found something else, but we don't know specifically what it is.
6323 S.Diag(Arg->getBeginLoc(), diag::err_template_arg_not_pointer_to_member_form)
6324 << Arg->getSourceRange();
6325 S.Diag(DRE->getDecl()->getLocation(), diag::note_template_arg_refers_here);
6329 /// Check a template argument against its corresponding
6330 /// non-type template parameter.
6332 /// This routine implements the semantics of C++ [temp.arg.nontype].
6333 /// If an error occurred, it returns ExprError(); otherwise, it
6334 /// returns the converted template argument. \p ParamType is the
6335 /// type of the non-type template parameter after it has been instantiated.
6336 ExprResult Sema::CheckTemplateArgument(NonTypeTemplateParmDecl *Param,
6337 QualType ParamType, Expr *Arg,
6338 TemplateArgument &Converted,
6339 CheckTemplateArgumentKind CTAK) {
6340 SourceLocation StartLoc = Arg->getBeginLoc();
6342 // If the parameter type somehow involves auto, deduce the type now.
6343 if (getLangOpts().CPlusPlus17 && ParamType->isUndeducedType()) {
6344 // During template argument deduction, we allow 'decltype(auto)' to
6345 // match an arbitrary dependent argument.
6346 // FIXME: The language rules don't say what happens in this case.
6347 // FIXME: We get an opaque dependent type out of decltype(auto) if the
6348 // expression is merely instantiation-dependent; is this enough?
6349 if (CTAK == CTAK_Deduced && Arg->isTypeDependent()) {
6350 auto *AT = dyn_cast<AutoType>(ParamType);
6351 if (AT && AT->isDecltypeAuto()) {
6352 Converted = TemplateArgument(Arg);
6357 // When checking a deduced template argument, deduce from its type even if
6358 // the type is dependent, in order to check the types of non-type template
6359 // arguments line up properly in partial ordering.
6360 Optional<unsigned> Depth = Param->getDepth() + 1;
6361 Expr *DeductionArg = Arg;
6362 if (auto *PE = dyn_cast<PackExpansionExpr>(DeductionArg))
6363 DeductionArg = PE->getPattern();
6365 Context.getTrivialTypeSourceInfo(ParamType, Param->getLocation()),
6366 DeductionArg, ParamType, Depth) == DAR_Failed) {
6367 Diag(Arg->getExprLoc(),
6368 diag::err_non_type_template_parm_type_deduction_failure)
6369 << Param->getDeclName() << Param->getType() << Arg->getType()
6370 << Arg->getSourceRange();
6371 Diag(Param->getLocation(), diag::note_template_param_here);
6374 // CheckNonTypeTemplateParameterType will produce a diagnostic if there's
6375 // an error. The error message normally references the parameter
6376 // declaration, but here we'll pass the argument location because that's
6377 // where the parameter type is deduced.
6378 ParamType = CheckNonTypeTemplateParameterType(ParamType, Arg->getExprLoc());
6379 if (ParamType.isNull()) {
6380 Diag(Param->getLocation(), diag::note_template_param_here);
6385 // We should have already dropped all cv-qualifiers by now.
6386 assert(!ParamType.hasQualifiers() &&
6387 "non-type template parameter type cannot be qualified");
6389 if (CTAK == CTAK_Deduced &&
6390 !Context.hasSameType(ParamType.getNonLValueExprType(Context),
6392 // FIXME: If either type is dependent, we skip the check. This isn't
6393 // correct, since during deduction we're supposed to have replaced each
6394 // template parameter with some unique (non-dependent) placeholder.
6395 // FIXME: If the argument type contains 'auto', we carry on and fail the
6396 // type check in order to force specific types to be more specialized than
6397 // 'auto'. It's not clear how partial ordering with 'auto' is supposed to
6399 if ((ParamType->isDependentType() || Arg->isTypeDependent()) &&
6400 !Arg->getType()->getContainedAutoType()) {
6401 Converted = TemplateArgument(Arg);
6404 // FIXME: This attempts to implement C++ [temp.deduct.type]p17. Per DR1770,
6405 // we should actually be checking the type of the template argument in P,
6406 // not the type of the template argument deduced from A, against the
6407 // template parameter type.
6408 Diag(StartLoc, diag::err_deduced_non_type_template_arg_type_mismatch)
6410 << ParamType.getUnqualifiedType();
6411 Diag(Param->getLocation(), diag::note_template_param_here);
6415 // If either the parameter has a dependent type or the argument is
6416 // type-dependent, there's nothing we can check now. The argument only
6417 // contains an unexpanded pack during partial ordering, and there's
6418 // nothing more we can check in that case.
6419 if (ParamType->isDependentType() || Arg->isTypeDependent() ||
6420 Arg->containsUnexpandedParameterPack()) {
6421 // Force the argument to the type of the parameter to maintain invariants.
6422 auto *PE = dyn_cast<PackExpansionExpr>(Arg);
6424 Arg = PE->getPattern();
6425 ExprResult E = ImpCastExprToType(
6426 Arg, ParamType.getNonLValueExprType(Context), CK_Dependent,
6427 ParamType->isLValueReferenceType() ? VK_LValue :
6428 ParamType->isRValueReferenceType() ? VK_XValue : VK_RValue);
6432 // Recreate a pack expansion if we unwrapped one.
6434 PackExpansionExpr(E.get()->getType(), E.get(), PE->getEllipsisLoc(),
6435 PE->getNumExpansions());
6437 Converted = TemplateArgument(E.get());
6441 // The initialization of the parameter from the argument is
6442 // a constant-evaluated context.
6443 EnterExpressionEvaluationContext ConstantEvaluated(
6444 *this, Sema::ExpressionEvaluationContext::ConstantEvaluated);
6446 if (getLangOpts().CPlusPlus17) {
6447 // C++17 [temp.arg.nontype]p1:
6448 // A template-argument for a non-type template parameter shall be
6449 // a converted constant expression of the type of the template-parameter.
6451 ExprResult ArgResult = CheckConvertedConstantExpression(
6452 Arg, ParamType, Value, CCEK_TemplateArg);
6453 if (ArgResult.isInvalid())
6456 // For a value-dependent argument, CheckConvertedConstantExpression is
6457 // permitted (and expected) to be unable to determine a value.
6458 if (ArgResult.get()->isValueDependent()) {
6459 Converted = TemplateArgument(ArgResult.get());
6463 QualType CanonParamType = Context.getCanonicalType(ParamType);
6465 // Convert the APValue to a TemplateArgument.
6466 switch (Value.getKind()) {
6468 assert(ParamType->isNullPtrType());
6469 Converted = TemplateArgument(CanonParamType, /*isNullPtr*/true);
6471 case APValue::Indeterminate:
6472 llvm_unreachable("result of constant evaluation should be initialized");
6475 assert(ParamType->isIntegralOrEnumerationType());
6476 Converted = TemplateArgument(Context, Value.getInt(), CanonParamType);
6478 case APValue::MemberPointer: {
6479 assert(ParamType->isMemberPointerType());
6481 // FIXME: We need TemplateArgument representation and mangling for these.
6482 if (!Value.getMemberPointerPath().empty()) {
6483 Diag(Arg->getBeginLoc(),
6484 diag::err_template_arg_member_ptr_base_derived_not_supported)
6485 << Value.getMemberPointerDecl() << ParamType
6486 << Arg->getSourceRange();
6490 auto *VD = const_cast<ValueDecl*>(Value.getMemberPointerDecl());
6491 Converted = VD ? TemplateArgument(VD, CanonParamType)
6492 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6495 case APValue::LValue: {
6496 // For a non-type template-parameter of pointer or reference type,
6497 // the value of the constant expression shall not refer to
6498 assert(ParamType->isPointerType() || ParamType->isReferenceType() ||
6499 ParamType->isNullPtrType());
6500 // -- a temporary object
6501 // -- a string literal
6502 // -- the result of a typeid expression, or
6503 // -- a predefined __func__ variable
6504 APValue::LValueBase Base = Value.getLValueBase();
6505 auto *VD = const_cast<ValueDecl *>(Base.dyn_cast<const ValueDecl *>());
6507 auto *E = Base.dyn_cast<const Expr *>();
6508 if (E && isa<CXXUuidofExpr>(E)) {
6509 Converted = TemplateArgument(ArgResult.get()->IgnoreImpCasts());
6512 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_decl_ref)
6513 << Arg->getSourceRange();
6517 if (Value.hasLValuePath() && Value.getLValuePath().size() == 1 &&
6518 VD && VD->getType()->isArrayType() &&
6519 Value.getLValuePath()[0].getAsArrayIndex() == 0 &&
6520 !Value.isLValueOnePastTheEnd() && ParamType->isPointerType()) {
6521 // Per defect report (no number yet):
6522 // ... other than a pointer to the first element of a complete array
6524 } else if (!Value.hasLValuePath() || Value.getLValuePath().size() ||
6525 Value.isLValueOnePastTheEnd()) {
6526 Diag(StartLoc, diag::err_non_type_template_arg_subobject)
6527 << Value.getAsString(Context, ParamType);
6530 assert((VD || !ParamType->isReferenceType()) &&
6531 "null reference should not be a constant expression");
6532 assert((!VD || !ParamType->isNullPtrType()) &&
6533 "non-null value of type nullptr_t?");
6534 Converted = VD ? TemplateArgument(VD, CanonParamType)
6535 : TemplateArgument(CanonParamType, /*isNullPtr*/true);
6538 case APValue::AddrLabelDiff:
6539 return Diag(StartLoc, diag::err_non_type_template_arg_addr_label_diff);
6540 case APValue::FixedPoint:
6541 case APValue::Float:
6542 case APValue::ComplexInt:
6543 case APValue::ComplexFloat:
6544 case APValue::Vector:
6545 case APValue::Array:
6546 case APValue::Struct:
6547 case APValue::Union:
6548 llvm_unreachable("invalid kind for template argument");
6551 return ArgResult.get();
6554 // C++ [temp.arg.nontype]p5:
6555 // The following conversions are performed on each expression used
6556 // as a non-type template-argument. If a non-type
6557 // template-argument cannot be converted to the type of the
6558 // corresponding template-parameter then the program is
6560 if (ParamType->isIntegralOrEnumerationType()) {
6562 // -- for a non-type template-parameter of integral or
6563 // enumeration type, conversions permitted in a converted
6564 // constant expression are applied.
6567 // -- for a non-type template-parameter of integral or
6568 // enumeration type, integral promotions (4.5) and integral
6569 // conversions (4.7) are applied.
6571 if (getLangOpts().CPlusPlus11) {
6572 // C++ [temp.arg.nontype]p1:
6573 // A template-argument for a non-type, non-template template-parameter
6576 // -- for a non-type template-parameter of integral or enumeration
6577 // type, a converted constant expression of the type of the
6578 // template-parameter; or
6580 ExprResult ArgResult =
6581 CheckConvertedConstantExpression(Arg, ParamType, Value,
6583 if (ArgResult.isInvalid())
6586 // We can't check arbitrary value-dependent arguments.
6587 if (ArgResult.get()->isValueDependent()) {
6588 Converted = TemplateArgument(ArgResult.get());
6592 // Widen the argument value to sizeof(parameter type). This is almost
6593 // always a no-op, except when the parameter type is bool. In
6594 // that case, this may extend the argument from 1 bit to 8 bits.
6595 QualType IntegerType = ParamType;
6596 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6597 IntegerType = Enum->getDecl()->getIntegerType();
6598 Value = Value.extOrTrunc(Context.getTypeSize(IntegerType));
6600 Converted = TemplateArgument(Context, Value,
6601 Context.getCanonicalType(ParamType));
6605 ExprResult ArgResult = DefaultLvalueConversion(Arg);
6606 if (ArgResult.isInvalid())
6608 Arg = ArgResult.get();
6610 QualType ArgType = Arg->getType();
6612 // C++ [temp.arg.nontype]p1:
6613 // A template-argument for a non-type, non-template
6614 // template-parameter shall be one of:
6616 // -- an integral constant-expression of integral or enumeration
6618 // -- the name of a non-type template-parameter; or
6620 if (!ArgType->isIntegralOrEnumerationType()) {
6621 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_integral_or_enumeral)
6622 << ArgType << Arg->getSourceRange();
6623 Diag(Param->getLocation(), diag::note_template_param_here);
6625 } else if (!Arg->isValueDependent()) {
6626 class TmplArgICEDiagnoser : public VerifyICEDiagnoser {
6630 TmplArgICEDiagnoser(QualType T) : T(T) { }
6632 void diagnoseNotICE(Sema &S, SourceLocation Loc,
6633 SourceRange SR) override {
6634 S.Diag(Loc, diag::err_template_arg_not_ice) << T << SR;
6636 } Diagnoser(ArgType);
6638 Arg = VerifyIntegerConstantExpression(Arg, &Value, Diagnoser,
6644 // From here on out, all we care about is the unqualified form
6645 // of the argument type.
6646 ArgType = ArgType.getUnqualifiedType();
6648 // Try to convert the argument to the parameter's type.
6649 if (Context.hasSameType(ParamType, ArgType)) {
6650 // Okay: no conversion necessary
6651 } else if (ParamType->isBooleanType()) {
6652 // This is an integral-to-boolean conversion.
6653 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralToBoolean).get();
6654 } else if (IsIntegralPromotion(Arg, ArgType, ParamType) ||
6655 !ParamType->isEnumeralType()) {
6656 // This is an integral promotion or conversion.
6657 Arg = ImpCastExprToType(Arg, ParamType, CK_IntegralCast).get();
6659 // We can't perform this conversion.
6660 Diag(Arg->getBeginLoc(), diag::err_template_arg_not_convertible)
6661 << Arg->getType() << ParamType << Arg->getSourceRange();
6662 Diag(Param->getLocation(), diag::note_template_param_here);
6666 // Add the value of this argument to the list of converted
6667 // arguments. We use the bitwidth and signedness of the template
6669 if (Arg->isValueDependent()) {
6670 // The argument is value-dependent. Create a new
6671 // TemplateArgument with the converted expression.
6672 Converted = TemplateArgument(Arg);
6676 QualType IntegerType = Context.getCanonicalType(ParamType);
6677 if (const EnumType *Enum = IntegerType->getAs<EnumType>())
6678 IntegerType = Context.getCanonicalType(Enum->getDecl()->getIntegerType());
6680 if (ParamType->isBooleanType()) {
6681 // Value must be zero or one.
6683 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6684 if (Value.getBitWidth() != AllowedBits)
6685 Value = Value.extOrTrunc(AllowedBits);
6686 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6688 llvm::APSInt OldValue = Value;
6690 // Coerce the template argument's value to the value it will have
6691 // based on the template parameter's type.
6692 unsigned AllowedBits = Context.getTypeSize(IntegerType);
6693 if (Value.getBitWidth() != AllowedBits)
6694 Value = Value.extOrTrunc(AllowedBits);
6695 Value.setIsSigned(IntegerType->isSignedIntegerOrEnumerationType());
6697 // Complain if an unsigned parameter received a negative value.
6698 if (IntegerType->isUnsignedIntegerOrEnumerationType()
6699 && (OldValue.isSigned() && OldValue.isNegative())) {
6700 Diag(Arg->getBeginLoc(), diag::warn_template_arg_negative)
6701 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6702 << Arg->getSourceRange();
6703 Diag(Param->getLocation(), diag::note_template_param_here);
6706 // Complain if we overflowed the template parameter's type.
6707 unsigned RequiredBits;
6708 if (IntegerType->isUnsignedIntegerOrEnumerationType())
6709 RequiredBits = OldValue.getActiveBits();
6710 else if (OldValue.isUnsigned())
6711 RequiredBits = OldValue.getActiveBits() + 1;
6713 RequiredBits = OldValue.getMinSignedBits();
6714 if (RequiredBits > AllowedBits) {
6715 Diag(Arg->getBeginLoc(), diag::warn_template_arg_too_large)
6716 << OldValue.toString(10) << Value.toString(10) << Param->getType()
6717 << Arg->getSourceRange();
6718 Diag(Param->getLocation(), diag::note_template_param_here);
6722 Converted = TemplateArgument(Context, Value,
6723 ParamType->isEnumeralType()
6724 ? Context.getCanonicalType(ParamType)
6729 QualType ArgType = Arg->getType();
6730 DeclAccessPair FoundResult; // temporary for ResolveOverloadedFunction
6732 // Handle pointer-to-function, reference-to-function, and
6733 // pointer-to-member-function all in (roughly) the same way.
6734 if (// -- For a non-type template-parameter of type pointer to
6735 // function, only the function-to-pointer conversion (4.3) is
6736 // applied. If the template-argument represents a set of
6737 // overloaded functions (or a pointer to such), the matching
6738 // function is selected from the set (13.4).
6739 (ParamType->isPointerType() &&
6740 ParamType->castAs<PointerType>()->getPointeeType()->isFunctionType()) ||
6741 // -- For a non-type template-parameter of type reference to
6742 // function, no conversions apply. If the template-argument
6743 // represents a set of overloaded functions, the matching
6744 // function is selected from the set (13.4).
6745 (ParamType->isReferenceType() &&
6746 ParamType->castAs<ReferenceType>()->getPointeeType()->isFunctionType()) ||
6747 // -- For a non-type template-parameter of type pointer to
6748 // member function, no conversions apply. If the
6749 // template-argument represents a set of overloaded member
6750 // functions, the matching member function is selected from
6752 (ParamType->isMemberPointerType() &&
6753 ParamType->castAs<MemberPointerType>()->getPointeeType()
6754 ->isFunctionType())) {
6756 if (Arg->getType() == Context.OverloadTy) {
6757 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg, ParamType,
6760 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6763 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6764 ArgType = Arg->getType();
6769 if (!ParamType->isMemberPointerType()) {
6770 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6777 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6783 if (ParamType->isPointerType()) {
6784 // -- for a non-type template-parameter of type pointer to
6785 // object, qualification conversions (4.4) and the
6786 // array-to-pointer conversion (4.2) are applied.
6787 // C++0x also allows a value of std::nullptr_t.
6788 assert(ParamType->getPointeeType()->isIncompleteOrObjectType() &&
6789 "Only object pointers allowed here");
6791 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6798 if (const ReferenceType *ParamRefType = ParamType->getAs<ReferenceType>()) {
6799 // -- For a non-type template-parameter of type reference to
6800 // object, no conversions apply. The type referred to by the
6801 // reference may be more cv-qualified than the (otherwise
6802 // identical) type of the template-argument. The
6803 // template-parameter is bound directly to the
6804 // template-argument, which must be an lvalue.
6805 assert(ParamRefType->getPointeeType()->isIncompleteOrObjectType() &&
6806 "Only object references allowed here");
6808 if (Arg->getType() == Context.OverloadTy) {
6809 if (FunctionDecl *Fn = ResolveAddressOfOverloadedFunction(Arg,
6810 ParamRefType->getPointeeType(),
6813 if (DiagnoseUseOfDecl(Fn, Arg->getBeginLoc()))
6816 Arg = FixOverloadedFunctionReference(Arg, FoundResult, Fn);
6817 ArgType = Arg->getType();
6822 if (CheckTemplateArgumentAddressOfObjectOrFunction(*this, Param,
6829 // Deal with parameters of type std::nullptr_t.
6830 if (ParamType->isNullPtrType()) {
6831 if (Arg->isTypeDependent() || Arg->isValueDependent()) {
6832 Converted = TemplateArgument(Arg);
6836 switch (isNullPointerValueTemplateArgument(*this, Param, ParamType, Arg)) {
6837 case NPV_NotNullPointer:
6838 Diag(Arg->getExprLoc(), diag::err_template_arg_not_convertible)
6839 << Arg->getType() << ParamType;
6840 Diag(Param->getLocation(), diag::note_template_param_here);
6846 case NPV_NullPointer:
6847 Diag(Arg->getExprLoc(), diag::warn_cxx98_compat_template_arg_null);
6848 Converted = TemplateArgument(Context.getCanonicalType(ParamType),
6854 // -- For a non-type template-parameter of type pointer to data
6855 // member, qualification conversions (4.4) are applied.
6856 assert(ParamType->isMemberPointerType() && "Only pointers to members remain");
6858 if (CheckTemplateArgumentPointerToMember(*this, Param, ParamType, Arg,
6864 static void DiagnoseTemplateParameterListArityMismatch(
6865 Sema &S, TemplateParameterList *New, TemplateParameterList *Old,
6866 Sema::TemplateParameterListEqualKind Kind, SourceLocation TemplateArgLoc);
6868 /// Check a template argument against its corresponding
6869 /// template template parameter.
6871 /// This routine implements the semantics of C++ [temp.arg.template].
6872 /// It returns true if an error occurred, and false otherwise.
6873 bool Sema::CheckTemplateTemplateArgument(TemplateParameterList *Params,
6874 TemplateArgumentLoc &Arg) {
6875 TemplateName Name = Arg.getArgument().getAsTemplateOrTemplatePattern();
6876 TemplateDecl *Template = Name.getAsTemplateDecl();
6878 // Any dependent template name is fine.
6879 assert(Name.isDependent() && "Non-dependent template isn't a declaration?");
6883 if (Template->isInvalidDecl())
6886 // C++0x [temp.arg.template]p1:
6887 // A template-argument for a template template-parameter shall be
6888 // the name of a class template or an alias template, expressed as an
6889 // id-expression. When the template-argument names a class template, only
6890 // primary class templates are considered when matching the
6891 // template template argument with the corresponding parameter;
6892 // partial specializations are not considered even if their
6893 // parameter lists match that of the template template parameter.
6895 // Note that we also allow template template parameters here, which
6896 // will happen when we are dealing with, e.g., class template
6897 // partial specializations.
6898 if (!isa<ClassTemplateDecl>(Template) &&
6899 !isa<TemplateTemplateParmDecl>(Template) &&
6900 !isa<TypeAliasTemplateDecl>(Template) &&
6901 !isa<BuiltinTemplateDecl>(Template)) {
6902 assert(isa<FunctionTemplateDecl>(Template) &&
6903 "Only function templates are possible here");
6904 Diag(Arg.getLocation(), diag::err_template_arg_not_valid_template);
6905 Diag(Template->getLocation(), diag::note_template_arg_refers_here_func)
6909 // C++1z [temp.arg.template]p3: (DR 150)
6910 // A template-argument matches a template template-parameter P when P
6911 // is at least as specialized as the template-argument A.
6912 if (getLangOpts().RelaxedTemplateTemplateArgs) {
6913 // Quick check for the common case:
6914 // If P contains a parameter pack, then A [...] matches P if each of A's
6915 // template parameters matches the corresponding template parameter in
6916 // the template-parameter-list of P.
6917 if (TemplateParameterListsAreEqual(
6918 Template->getTemplateParameters(), Params, false,
6919 TPL_TemplateTemplateArgumentMatch, Arg.getLocation()))
6922 if (isTemplateTemplateParameterAtLeastAsSpecializedAs(Params, Template,
6925 // FIXME: Produce better diagnostics for deduction failures.
6928 return !TemplateParameterListsAreEqual(Template->getTemplateParameters(),
6931 TPL_TemplateTemplateArgumentMatch,
6935 /// Given a non-type template argument that refers to a
6936 /// declaration and the type of its corresponding non-type template
6937 /// parameter, produce an expression that properly refers to that
6940 Sema::BuildExpressionFromDeclTemplateArgument(const TemplateArgument &Arg,
6942 SourceLocation Loc) {
6943 // C++ [temp.param]p8:
6945 // A non-type template-parameter of type "array of T" or
6946 // "function returning T" is adjusted to be of type "pointer to
6947 // T" or "pointer to function returning T", respectively.
6948 if (ParamType->isArrayType())
6949 ParamType = Context.getArrayDecayedType(ParamType);
6950 else if (ParamType->isFunctionType())
6951 ParamType = Context.getPointerType(ParamType);
6953 // For a NULL non-type template argument, return nullptr casted to the
6954 // parameter's type.
6955 if (Arg.getKind() == TemplateArgument::NullPtr) {
6956 return ImpCastExprToType(
6957 new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc),
6959 ParamType->getAs<MemberPointerType>()
6960 ? CK_NullToMemberPointer
6961 : CK_NullToPointer);
6963 assert(Arg.getKind() == TemplateArgument::Declaration &&
6964 "Only declaration template arguments permitted here");
6966 ValueDecl *VD = Arg.getAsDecl();
6968 if (VD->getDeclContext()->isRecord() &&
6969 (isa<CXXMethodDecl>(VD) || isa<FieldDecl>(VD) ||
6970 isa<IndirectFieldDecl>(VD))) {
6971 // If the value is a class member, we might have a pointer-to-member.
6972 // Determine whether the non-type template template parameter is of
6973 // pointer-to-member type. If so, we need to build an appropriate
6974 // expression for a pointer-to-member, since a "normal" DeclRefExpr
6975 // would refer to the member itself.
6976 if (ParamType->isMemberPointerType()) {
6978 = Context.getTypeDeclType(cast<RecordDecl>(VD->getDeclContext()));
6979 NestedNameSpecifier *Qualifier
6980 = NestedNameSpecifier::Create(Context, nullptr, false,
6981 ClassType.getTypePtr());
6983 SS.MakeTrivial(Context, Qualifier, Loc);
6985 // The actual value-ness of this is unimportant, but for
6986 // internal consistency's sake, references to instance methods
6988 ExprValueKind VK = VK_LValue;
6989 if (isa<CXXMethodDecl>(VD) && cast<CXXMethodDecl>(VD)->isInstance())
6992 ExprResult RefExpr = BuildDeclRefExpr(VD,
6993 VD->getType().getNonReferenceType(),
6997 if (RefExpr.isInvalid())
7000 RefExpr = CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7002 // We might need to perform a trailing qualification conversion, since
7003 // the element type on the parameter could be more qualified than the
7004 // element type in the expression we constructed.
7005 bool ObjCLifetimeConversion;
7006 if (IsQualificationConversion(((Expr*) RefExpr.get())->getType(),
7007 ParamType.getUnqualifiedType(), false,
7008 ObjCLifetimeConversion))
7009 RefExpr = ImpCastExprToType(RefExpr.get(), ParamType.getUnqualifiedType(), CK_NoOp);
7011 assert(!RefExpr.isInvalid() &&
7012 Context.hasSameType(((Expr*) RefExpr.get())->getType(),
7013 ParamType.getUnqualifiedType()));
7018 QualType T = VD->getType().getNonReferenceType();
7020 if (ParamType->isPointerType()) {
7021 // When the non-type template parameter is a pointer, take the
7022 // address of the declaration.
7023 ExprResult RefExpr = BuildDeclRefExpr(VD, T, VK_LValue, Loc);
7024 if (RefExpr.isInvalid())
7027 if (!Context.hasSameUnqualifiedType(ParamType->getPointeeType(), T) &&
7028 (T->isFunctionType() || T->isArrayType())) {
7029 // Decay functions and arrays unless we're forming a pointer to array.
7030 RefExpr = DefaultFunctionArrayConversion(RefExpr.get());
7031 if (RefExpr.isInvalid())
7037 // Take the address of everything else
7038 return CreateBuiltinUnaryOp(Loc, UO_AddrOf, RefExpr.get());
7041 ExprValueKind VK = VK_RValue;
7043 // If the non-type template parameter has reference type, qualify the
7044 // resulting declaration reference with the extra qualifiers on the
7045 // type that the reference refers to.
7046 if (const ReferenceType *TargetRef = ParamType->getAs<ReferenceType>()) {
7048 T = Context.getQualifiedType(T,
7049 TargetRef->getPointeeType().getQualifiers());
7050 } else if (isa<FunctionDecl>(VD)) {
7051 // References to functions are always lvalues.
7055 return BuildDeclRefExpr(VD, T, VK, Loc);
7058 /// Construct a new expression that refers to the given
7059 /// integral template argument with the given source-location
7062 /// This routine takes care of the mapping from an integral template
7063 /// argument (which may have any integral type) to the appropriate
7066 Sema::BuildExpressionFromIntegralTemplateArgument(const TemplateArgument &Arg,
7067 SourceLocation Loc) {
7068 assert(Arg.getKind() == TemplateArgument::Integral &&
7069 "Operation is only valid for integral template arguments");
7070 QualType OrigT = Arg.getIntegralType();
7072 // If this is an enum type that we're instantiating, we need to use an integer
7073 // type the same size as the enumerator. We don't want to build an
7074 // IntegerLiteral with enum type. The integer type of an enum type can be of
7075 // any integral type with C++11 enum classes, make sure we create the right
7076 // type of literal for it.
7078 if (const EnumType *ET = OrigT->getAs<EnumType>())
7079 T = ET->getDecl()->getIntegerType();
7082 if (T->isAnyCharacterType()) {
7083 CharacterLiteral::CharacterKind Kind;
7084 if (T->isWideCharType())
7085 Kind = CharacterLiteral::Wide;
7086 else if (T->isChar8Type() && getLangOpts().Char8)
7087 Kind = CharacterLiteral::UTF8;
7088 else if (T->isChar16Type())
7089 Kind = CharacterLiteral::UTF16;
7090 else if (T->isChar32Type())
7091 Kind = CharacterLiteral::UTF32;
7093 Kind = CharacterLiteral::Ascii;
7095 E = new (Context) CharacterLiteral(Arg.getAsIntegral().getZExtValue(),
7097 } else if (T->isBooleanType()) {
7098 E = new (Context) CXXBoolLiteralExpr(Arg.getAsIntegral().getBoolValue(),
7100 } else if (T->isNullPtrType()) {
7101 E = new (Context) CXXNullPtrLiteralExpr(Context.NullPtrTy, Loc);
7103 E = IntegerLiteral::Create(Context, Arg.getAsIntegral(), T, Loc);
7106 if (OrigT->isEnumeralType()) {
7107 // FIXME: This is a hack. We need a better way to handle substituted
7108 // non-type template parameters.
7109 E = CStyleCastExpr::Create(Context, OrigT, VK_RValue, CK_IntegralCast, E,
7111 Context.getTrivialTypeSourceInfo(OrigT, Loc),
7118 /// Match two template parameters within template parameter lists.
7119 static bool MatchTemplateParameterKind(Sema &S, NamedDecl *New, NamedDecl *Old,
7121 Sema::TemplateParameterListEqualKind Kind,
7122 SourceLocation TemplateArgLoc) {
7123 // Check the actual kind (type, non-type, template).
7124 if (Old->getKind() != New->getKind()) {
7126 unsigned NextDiag = diag::err_template_param_different_kind;
7127 if (TemplateArgLoc.isValid()) {
7128 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7129 NextDiag = diag::note_template_param_different_kind;
7131 S.Diag(New->getLocation(), NextDiag)
7132 << (Kind != Sema::TPL_TemplateMatch);
7133 S.Diag(Old->getLocation(), diag::note_template_prev_declaration)
7134 << (Kind != Sema::TPL_TemplateMatch);
7140 // Check that both are parameter packs or neither are parameter packs.
7141 // However, if we are matching a template template argument to a
7142 // template template parameter, the template template parameter can have
7143 // a parameter pack where the template template argument does not.
7144 if (Old->isTemplateParameterPack() != New->isTemplateParameterPack() &&
7145 !(Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7146 Old->isTemplateParameterPack())) {
7148 unsigned NextDiag = diag::err_template_parameter_pack_non_pack;
7149 if (TemplateArgLoc.isValid()) {
7150 S.Diag(TemplateArgLoc,
7151 diag::err_template_arg_template_params_mismatch);
7152 NextDiag = diag::note_template_parameter_pack_non_pack;
7155 unsigned ParamKind = isa<TemplateTypeParmDecl>(New)? 0
7156 : isa<NonTypeTemplateParmDecl>(New)? 1
7158 S.Diag(New->getLocation(), NextDiag)
7159 << ParamKind << New->isParameterPack();
7160 S.Diag(Old->getLocation(), diag::note_template_parameter_pack_here)
7161 << ParamKind << Old->isParameterPack();
7167 // For non-type template parameters, check the type of the parameter.
7168 if (NonTypeTemplateParmDecl *OldNTTP
7169 = dyn_cast<NonTypeTemplateParmDecl>(Old)) {
7170 NonTypeTemplateParmDecl *NewNTTP = cast<NonTypeTemplateParmDecl>(New);
7172 // If we are matching a template template argument to a template
7173 // template parameter and one of the non-type template parameter types
7174 // is dependent, then we must wait until template instantiation time
7175 // to actually compare the arguments.
7176 if (Kind == Sema::TPL_TemplateTemplateArgumentMatch &&
7177 (OldNTTP->getType()->isDependentType() ||
7178 NewNTTP->getType()->isDependentType()))
7181 if (!S.Context.hasSameType(OldNTTP->getType(), NewNTTP->getType())) {
7183 unsigned NextDiag = diag::err_template_nontype_parm_different_type;
7184 if (TemplateArgLoc.isValid()) {
7185 S.Diag(TemplateArgLoc,
7186 diag::err_template_arg_template_params_mismatch);
7187 NextDiag = diag::note_template_nontype_parm_different_type;
7189 S.Diag(NewNTTP->getLocation(), NextDiag)
7190 << NewNTTP->getType()
7191 << (Kind != Sema::TPL_TemplateMatch);
7192 S.Diag(OldNTTP->getLocation(),
7193 diag::note_template_nontype_parm_prev_declaration)
7194 << OldNTTP->getType();
7203 // For template template parameters, check the template parameter types.
7204 // The template parameter lists of template template
7205 // parameters must agree.
7206 if (TemplateTemplateParmDecl *OldTTP
7207 = dyn_cast<TemplateTemplateParmDecl>(Old)) {
7208 TemplateTemplateParmDecl *NewTTP = cast<TemplateTemplateParmDecl>(New);
7209 return S.TemplateParameterListsAreEqual(NewTTP->getTemplateParameters(),
7210 OldTTP->getTemplateParameters(),
7212 (Kind == Sema::TPL_TemplateMatch
7213 ? Sema::TPL_TemplateTemplateParmMatch
7218 // TODO: Concepts: Match immediately-introduced-constraint for type
7224 /// Diagnose a known arity mismatch when comparing template argument
7227 void DiagnoseTemplateParameterListArityMismatch(Sema &S,
7228 TemplateParameterList *New,
7229 TemplateParameterList *Old,
7230 Sema::TemplateParameterListEqualKind Kind,
7231 SourceLocation TemplateArgLoc) {
7232 unsigned NextDiag = diag::err_template_param_list_different_arity;
7233 if (TemplateArgLoc.isValid()) {
7234 S.Diag(TemplateArgLoc, diag::err_template_arg_template_params_mismatch);
7235 NextDiag = diag::note_template_param_list_different_arity;
7237 S.Diag(New->getTemplateLoc(), NextDiag)
7238 << (New->size() > Old->size())
7239 << (Kind != Sema::TPL_TemplateMatch)
7240 << SourceRange(New->getTemplateLoc(), New->getRAngleLoc());
7241 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7242 << (Kind != Sema::TPL_TemplateMatch)
7243 << SourceRange(Old->getTemplateLoc(), Old->getRAngleLoc());
7247 DiagnoseTemplateParameterListRequiresClauseMismatch(Sema &S,
7248 TemplateParameterList *New,
7249 TemplateParameterList *Old){
7250 S.Diag(New->getTemplateLoc(), diag::err_template_different_requires_clause);
7251 S.Diag(Old->getTemplateLoc(), diag::note_template_prev_declaration)
7252 << /*declaration*/0;
7255 /// Determine whether the given template parameter lists are
7258 /// \param New The new template parameter list, typically written in the
7259 /// source code as part of a new template declaration.
7261 /// \param Old The old template parameter list, typically found via
7262 /// name lookup of the template declared with this template parameter
7265 /// \param Complain If true, this routine will produce a diagnostic if
7266 /// the template parameter lists are not equivalent.
7268 /// \param Kind describes how we are to match the template parameter lists.
7270 /// \param TemplateArgLoc If this source location is valid, then we
7271 /// are actually checking the template parameter list of a template
7272 /// argument (New) against the template parameter list of its
7273 /// corresponding template template parameter (Old). We produce
7274 /// slightly different diagnostics in this scenario.
7276 /// \returns True if the template parameter lists are equal, false
7279 Sema::TemplateParameterListsAreEqual(TemplateParameterList *New,
7280 TemplateParameterList *Old,
7282 TemplateParameterListEqualKind Kind,
7283 SourceLocation TemplateArgLoc) {
7284 if (Old->size() != New->size() && Kind != TPL_TemplateTemplateArgumentMatch) {
7286 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7292 // C++0x [temp.arg.template]p3:
7293 // A template-argument matches a template template-parameter (call it P)
7294 // when each of the template parameters in the template-parameter-list of
7295 // the template-argument's corresponding class template or alias template
7296 // (call it A) matches the corresponding template parameter in the
7297 // template-parameter-list of P. [...]
7298 TemplateParameterList::iterator NewParm = New->begin();
7299 TemplateParameterList::iterator NewParmEnd = New->end();
7300 for (TemplateParameterList::iterator OldParm = Old->begin(),
7301 OldParmEnd = Old->end();
7302 OldParm != OldParmEnd; ++OldParm) {
7303 if (Kind != TPL_TemplateTemplateArgumentMatch ||
7304 !(*OldParm)->isTemplateParameterPack()) {
7305 if (NewParm == NewParmEnd) {
7307 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7313 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7314 Kind, TemplateArgLoc))
7321 // C++0x [temp.arg.template]p3:
7322 // [...] When P's template- parameter-list contains a template parameter
7323 // pack (14.5.3), the template parameter pack will match zero or more
7324 // template parameters or template parameter packs in the
7325 // template-parameter-list of A with the same type and form as the
7326 // template parameter pack in P (ignoring whether those template
7327 // parameters are template parameter packs).
7328 for (; NewParm != NewParmEnd; ++NewParm) {
7329 if (!MatchTemplateParameterKind(*this, *NewParm, *OldParm, Complain,
7330 Kind, TemplateArgLoc))
7335 // Make sure we exhausted all of the arguments.
7336 if (NewParm != NewParmEnd) {
7338 DiagnoseTemplateParameterListArityMismatch(*this, New, Old, Kind,
7344 if (Kind != TPL_TemplateTemplateArgumentMatch) {
7345 const Expr *NewRC = New->getRequiresClause();
7346 const Expr *OldRC = Old->getRequiresClause();
7347 if (!NewRC != !OldRC) {
7349 DiagnoseTemplateParameterListRequiresClauseMismatch(*this, New, Old);
7354 llvm::FoldingSetNodeID OldRCID, NewRCID;
7355 OldRC->Profile(OldRCID, Context, /*Canonical=*/true);
7356 NewRC->Profile(NewRCID, Context, /*Canonical=*/true);
7357 if (OldRCID != NewRCID) {
7359 DiagnoseTemplateParameterListRequiresClauseMismatch(*this, New, Old);
7368 /// Check whether a template can be declared within this scope.
7370 /// If the template declaration is valid in this scope, returns
7371 /// false. Otherwise, issues a diagnostic and returns true.
7373 Sema::CheckTemplateDeclScope(Scope *S, TemplateParameterList *TemplateParams) {
7377 // Find the nearest enclosing declaration scope.
7378 while ((S->getFlags() & Scope::DeclScope) == 0 ||
7379 (S->getFlags() & Scope::TemplateParamScope) != 0)
7383 // A template [...] shall not have C linkage.
7384 DeclContext *Ctx = S->getEntity();
7385 if (Ctx && Ctx->isExternCContext()) {
7386 Diag(TemplateParams->getTemplateLoc(), diag::err_template_linkage)
7387 << TemplateParams->getSourceRange();
7388 if (const LinkageSpecDecl *LSD = Ctx->getExternCContext())
7389 Diag(LSD->getExternLoc(), diag::note_extern_c_begins_here);
7392 Ctx = Ctx->getRedeclContext();
7395 // A template-declaration can appear only as a namespace scope or
7396 // class scope declaration.
7398 if (Ctx->isFileContext())
7400 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(Ctx)) {
7401 // C++ [temp.mem]p2:
7402 // A local class shall not have member templates.
7403 if (RD->isLocalClass())
7404 return Diag(TemplateParams->getTemplateLoc(),
7405 diag::err_template_inside_local_class)
7406 << TemplateParams->getSourceRange();
7412 return Diag(TemplateParams->getTemplateLoc(),
7413 diag::err_template_outside_namespace_or_class_scope)
7414 << TemplateParams->getSourceRange();
7417 /// Determine what kind of template specialization the given declaration
7419 static TemplateSpecializationKind getTemplateSpecializationKind(Decl *D) {
7421 return TSK_Undeclared;
7423 if (CXXRecordDecl *Record = dyn_cast<CXXRecordDecl>(D))
7424 return Record->getTemplateSpecializationKind();
7425 if (FunctionDecl *Function = dyn_cast<FunctionDecl>(D))
7426 return Function->getTemplateSpecializationKind();
7427 if (VarDecl *Var = dyn_cast<VarDecl>(D))
7428 return Var->getTemplateSpecializationKind();
7430 return TSK_Undeclared;
7433 /// Check whether a specialization is well-formed in the current
7436 /// This routine determines whether a template specialization can be declared
7437 /// in the current context (C++ [temp.expl.spec]p2).
7439 /// \param S the semantic analysis object for which this check is being
7442 /// \param Specialized the entity being specialized or instantiated, which
7443 /// may be a kind of template (class template, function template, etc.) or
7444 /// a member of a class template (member function, static data member,
7447 /// \param PrevDecl the previous declaration of this entity, if any.
7449 /// \param Loc the location of the explicit specialization or instantiation of
7452 /// \param IsPartialSpecialization whether this is a partial specialization of
7453 /// a class template.
7455 /// \returns true if there was an error that we cannot recover from, false
7457 static bool CheckTemplateSpecializationScope(Sema &S,
7458 NamedDecl *Specialized,
7459 NamedDecl *PrevDecl,
7461 bool IsPartialSpecialization) {
7462 // Keep these "kind" numbers in sync with the %select statements in the
7463 // various diagnostics emitted by this routine.
7465 if (isa<ClassTemplateDecl>(Specialized))
7466 EntityKind = IsPartialSpecialization? 1 : 0;
7467 else if (isa<VarTemplateDecl>(Specialized))
7468 EntityKind = IsPartialSpecialization ? 3 : 2;
7469 else if (isa<FunctionTemplateDecl>(Specialized))
7471 else if (isa<CXXMethodDecl>(Specialized))
7473 else if (isa<VarDecl>(Specialized))
7475 else if (isa<RecordDecl>(Specialized))
7477 else if (isa<EnumDecl>(Specialized) && S.getLangOpts().CPlusPlus11)
7480 S.Diag(Loc, diag::err_template_spec_unknown_kind)
7481 << S.getLangOpts().CPlusPlus11;
7482 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7486 // C++ [temp.expl.spec]p2:
7487 // An explicit specialization may be declared in any scope in which
7488 // the corresponding primary template may be defined.
7489 if (S.CurContext->getRedeclContext()->isFunctionOrMethod()) {
7490 S.Diag(Loc, diag::err_template_spec_decl_function_scope)
7495 // C++ [temp.class.spec]p6:
7496 // A class template partial specialization may be declared in any
7497 // scope in which the primary template may be defined.
7498 DeclContext *SpecializedContext =
7499 Specialized->getDeclContext()->getRedeclContext();
7500 DeclContext *DC = S.CurContext->getRedeclContext();
7502 // Make sure that this redeclaration (or definition) occurs in the same
7503 // scope or an enclosing namespace.
7504 if (!(DC->isFileContext() ? DC->Encloses(SpecializedContext)
7505 : DC->Equals(SpecializedContext))) {
7506 if (isa<TranslationUnitDecl>(SpecializedContext))
7507 S.Diag(Loc, diag::err_template_spec_redecl_global_scope)
7508 << EntityKind << Specialized;
7510 auto *ND = cast<NamedDecl>(SpecializedContext);
7511 int Diag = diag::err_template_spec_redecl_out_of_scope;
7512 if (S.getLangOpts().MicrosoftExt && !DC->isRecord())
7513 Diag = diag::ext_ms_template_spec_redecl_out_of_scope;
7514 S.Diag(Loc, Diag) << EntityKind << Specialized
7515 << ND << isa<CXXRecordDecl>(ND);
7518 S.Diag(Specialized->getLocation(), diag::note_specialized_entity);
7520 // Don't allow specializing in the wrong class during error recovery.
7521 // Otherwise, things can go horribly wrong.
7529 static SourceRange findTemplateParameterInType(unsigned Depth, Expr *E) {
7530 if (!E->isTypeDependent())
7531 return SourceLocation();
7532 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7533 Checker.TraverseStmt(E);
7534 if (Checker.MatchLoc.isInvalid())
7535 return E->getSourceRange();
7536 return Checker.MatchLoc;
7539 static SourceRange findTemplateParameter(unsigned Depth, TypeLoc TL) {
7540 if (!TL.getType()->isDependentType())
7541 return SourceLocation();
7542 DependencyChecker Checker(Depth, /*IgnoreNonTypeDependent*/true);
7543 Checker.TraverseTypeLoc(TL);
7544 if (Checker.MatchLoc.isInvalid())
7545 return TL.getSourceRange();
7546 return Checker.MatchLoc;
7549 /// Subroutine of Sema::CheckTemplatePartialSpecializationArgs
7550 /// that checks non-type template partial specialization arguments.
7551 static bool CheckNonTypeTemplatePartialSpecializationArgs(
7552 Sema &S, SourceLocation TemplateNameLoc, NonTypeTemplateParmDecl *Param,
7553 const TemplateArgument *Args, unsigned NumArgs, bool IsDefaultArgument) {
7554 for (unsigned I = 0; I != NumArgs; ++I) {
7555 if (Args[I].getKind() == TemplateArgument::Pack) {
7556 if (CheckNonTypeTemplatePartialSpecializationArgs(
7557 S, TemplateNameLoc, Param, Args[I].pack_begin(),
7558 Args[I].pack_size(), IsDefaultArgument))
7564 if (Args[I].getKind() != TemplateArgument::Expression)
7567 Expr *ArgExpr = Args[I].getAsExpr();
7569 // We can have a pack expansion of any of the bullets below.
7570 if (PackExpansionExpr *Expansion = dyn_cast<PackExpansionExpr>(ArgExpr))
7571 ArgExpr = Expansion->getPattern();
7573 // Strip off any implicit casts we added as part of type checking.
7574 while (ImplicitCastExpr *ICE = dyn_cast<ImplicitCastExpr>(ArgExpr))
7575 ArgExpr = ICE->getSubExpr();
7577 // C++ [temp.class.spec]p8:
7578 // A non-type argument is non-specialized if it is the name of a
7579 // non-type parameter. All other non-type arguments are
7582 // Below, we check the two conditions that only apply to
7583 // specialized non-type arguments, so skip any non-specialized
7585 if (DeclRefExpr *DRE = dyn_cast<DeclRefExpr>(ArgExpr))
7586 if (isa<NonTypeTemplateParmDecl>(DRE->getDecl()))
7589 // C++ [temp.class.spec]p9:
7590 // Within the argument list of a class template partial
7591 // specialization, the following restrictions apply:
7592 // -- A partially specialized non-type argument expression
7593 // shall not involve a template parameter of the partial
7594 // specialization except when the argument expression is a
7595 // simple identifier.
7596 // -- The type of a template parameter corresponding to a
7597 // specialized non-type argument shall not be dependent on a
7598 // parameter of the specialization.
7599 // DR1315 removes the first bullet, leaving an incoherent set of rules.
7600 // We implement a compromise between the original rules and DR1315:
7601 // -- A specialized non-type template argument shall not be
7602 // type-dependent and the corresponding template parameter
7603 // shall have a non-dependent type.
7604 SourceRange ParamUseRange =
7605 findTemplateParameterInType(Param->getDepth(), ArgExpr);
7606 if (ParamUseRange.isValid()) {
7607 if (IsDefaultArgument) {
7608 S.Diag(TemplateNameLoc,
7609 diag::err_dependent_non_type_arg_in_partial_spec);
7610 S.Diag(ParamUseRange.getBegin(),
7611 diag::note_dependent_non_type_default_arg_in_partial_spec)
7614 S.Diag(ParamUseRange.getBegin(),
7615 diag::err_dependent_non_type_arg_in_partial_spec)
7621 ParamUseRange = findTemplateParameter(
7622 Param->getDepth(), Param->getTypeSourceInfo()->getTypeLoc());
7623 if (ParamUseRange.isValid()) {
7624 S.Diag(IsDefaultArgument ? TemplateNameLoc : ArgExpr->getBeginLoc(),
7625 diag::err_dependent_typed_non_type_arg_in_partial_spec)
7626 << Param->getType();
7627 S.Diag(Param->getLocation(), diag::note_template_param_here)
7628 << (IsDefaultArgument ? ParamUseRange : SourceRange())
7637 /// Check the non-type template arguments of a class template
7638 /// partial specialization according to C++ [temp.class.spec]p9.
7640 /// \param TemplateNameLoc the location of the template name.
7641 /// \param PrimaryTemplate the template parameters of the primary class
7643 /// \param NumExplicit the number of explicitly-specified template arguments.
7644 /// \param TemplateArgs the template arguments of the class template
7645 /// partial specialization.
7647 /// \returns \c true if there was an error, \c false otherwise.
7648 bool Sema::CheckTemplatePartialSpecializationArgs(
7649 SourceLocation TemplateNameLoc, TemplateDecl *PrimaryTemplate,
7650 unsigned NumExplicit, ArrayRef<TemplateArgument> TemplateArgs) {
7651 // We have to be conservative when checking a template in a dependent
7653 if (PrimaryTemplate->getDeclContext()->isDependentContext())
7656 TemplateParameterList *TemplateParams =
7657 PrimaryTemplate->getTemplateParameters();
7658 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7659 NonTypeTemplateParmDecl *Param
7660 = dyn_cast<NonTypeTemplateParmDecl>(TemplateParams->getParam(I));
7664 if (CheckNonTypeTemplatePartialSpecializationArgs(*this, TemplateNameLoc,
7665 Param, &TemplateArgs[I],
7666 1, I >= NumExplicit))
7673 DeclResult Sema::ActOnClassTemplateSpecialization(
7674 Scope *S, unsigned TagSpec, TagUseKind TUK, SourceLocation KWLoc,
7675 SourceLocation ModulePrivateLoc, TemplateIdAnnotation &TemplateId,
7676 const ParsedAttributesView &Attr,
7677 MultiTemplateParamsArg TemplateParameterLists, SkipBodyInfo *SkipBody) {
7678 assert(TUK != TUK_Reference && "References are not specializations");
7680 CXXScopeSpec &SS = TemplateId.SS;
7682 // NOTE: KWLoc is the location of the tag keyword. This will instead
7683 // store the location of the outermost template keyword in the declaration.
7684 SourceLocation TemplateKWLoc = TemplateParameterLists.size() > 0
7685 ? TemplateParameterLists[0]->getTemplateLoc() : KWLoc;
7686 SourceLocation TemplateNameLoc = TemplateId.TemplateNameLoc;
7687 SourceLocation LAngleLoc = TemplateId.LAngleLoc;
7688 SourceLocation RAngleLoc = TemplateId.RAngleLoc;
7690 // Find the class template we're specializing
7691 TemplateName Name = TemplateId.Template.get();
7692 ClassTemplateDecl *ClassTemplate
7693 = dyn_cast_or_null<ClassTemplateDecl>(Name.getAsTemplateDecl());
7695 if (!ClassTemplate) {
7696 Diag(TemplateNameLoc, diag::err_not_class_template_specialization)
7697 << (Name.getAsTemplateDecl() &&
7698 isa<TemplateTemplateParmDecl>(Name.getAsTemplateDecl()));
7702 bool isMemberSpecialization = false;
7703 bool isPartialSpecialization = false;
7705 // Check the validity of the template headers that introduce this
7707 // FIXME: We probably shouldn't complain about these headers for
7708 // friend declarations.
7709 bool Invalid = false;
7710 TemplateParameterList *TemplateParams =
7711 MatchTemplateParametersToScopeSpecifier(
7712 KWLoc, TemplateNameLoc, SS, &TemplateId,
7713 TemplateParameterLists, TUK == TUK_Friend, isMemberSpecialization,
7718 if (TemplateParams && TemplateParams->size() > 0) {
7719 isPartialSpecialization = true;
7721 if (TUK == TUK_Friend) {
7722 Diag(KWLoc, diag::err_partial_specialization_friend)
7723 << SourceRange(LAngleLoc, RAngleLoc);
7727 // C++ [temp.class.spec]p10:
7728 // The template parameter list of a specialization shall not
7729 // contain default template argument values.
7730 for (unsigned I = 0, N = TemplateParams->size(); I != N; ++I) {
7731 Decl *Param = TemplateParams->getParam(I);
7732 if (TemplateTypeParmDecl *TTP = dyn_cast<TemplateTypeParmDecl>(Param)) {
7733 if (TTP->hasDefaultArgument()) {
7734 Diag(TTP->getDefaultArgumentLoc(),
7735 diag::err_default_arg_in_partial_spec);
7736 TTP->removeDefaultArgument();
7738 } else if (NonTypeTemplateParmDecl *NTTP
7739 = dyn_cast<NonTypeTemplateParmDecl>(Param)) {
7740 if (Expr *DefArg = NTTP->getDefaultArgument()) {
7741 Diag(NTTP->getDefaultArgumentLoc(),
7742 diag::err_default_arg_in_partial_spec)
7743 << DefArg->getSourceRange();
7744 NTTP->removeDefaultArgument();
7747 TemplateTemplateParmDecl *TTP = cast<TemplateTemplateParmDecl>(Param);
7748 if (TTP->hasDefaultArgument()) {
7749 Diag(TTP->getDefaultArgument().getLocation(),
7750 diag::err_default_arg_in_partial_spec)
7751 << TTP->getDefaultArgument().getSourceRange();
7752 TTP->removeDefaultArgument();
7756 } else if (TemplateParams) {
7757 if (TUK == TUK_Friend)
7758 Diag(KWLoc, diag::err_template_spec_friend)
7759 << FixItHint::CreateRemoval(
7760 SourceRange(TemplateParams->getTemplateLoc(),
7761 TemplateParams->getRAngleLoc()))
7762 << SourceRange(LAngleLoc, RAngleLoc);
7764 assert(TUK == TUK_Friend && "should have a 'template<>' for this decl");
7767 // Check that the specialization uses the same tag kind as the
7768 // original template.
7769 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
7770 assert(Kind != TTK_Enum && "Invalid enum tag in class template spec!");
7771 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
7772 Kind, TUK == TUK_Definition, KWLoc,
7773 ClassTemplate->getIdentifier())) {
7774 Diag(KWLoc, diag::err_use_with_wrong_tag)
7776 << FixItHint::CreateReplacement(KWLoc,
7777 ClassTemplate->getTemplatedDecl()->getKindName());
7778 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
7779 diag::note_previous_use);
7780 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
7783 // Translate the parser's template argument list in our AST format.
7784 TemplateArgumentListInfo TemplateArgs =
7785 makeTemplateArgumentListInfo(*this, TemplateId);
7787 // Check for unexpanded parameter packs in any of the template arguments.
7788 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
7789 if (DiagnoseUnexpandedParameterPack(TemplateArgs[I],
7790 UPPC_PartialSpecialization))
7793 // Check that the template argument list is well-formed for this
7795 SmallVector<TemplateArgument, 4> Converted;
7796 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
7797 TemplateArgs, false, Converted))
7800 // Find the class template (partial) specialization declaration that
7801 // corresponds to these arguments.
7802 if (isPartialSpecialization) {
7803 if (CheckTemplatePartialSpecializationArgs(TemplateNameLoc, ClassTemplate,
7804 TemplateArgs.size(), Converted))
7807 // FIXME: Move this to CheckTemplatePartialSpecializationArgs so we
7808 // also do it during instantiation.
7809 bool InstantiationDependent;
7810 if (!Name.isDependent() &&
7811 !TemplateSpecializationType::anyDependentTemplateArguments(
7812 TemplateArgs.arguments(), InstantiationDependent)) {
7813 Diag(TemplateNameLoc, diag::err_partial_spec_fully_specialized)
7814 << ClassTemplate->getDeclName();
7815 isPartialSpecialization = false;
7819 void *InsertPos = nullptr;
7820 ClassTemplateSpecializationDecl *PrevDecl = nullptr;
7822 if (isPartialSpecialization)
7823 // FIXME: Template parameter list matters, too
7824 PrevDecl = ClassTemplate->findPartialSpecialization(Converted, InsertPos);
7826 PrevDecl = ClassTemplate->findSpecialization(Converted, InsertPos);
7828 ClassTemplateSpecializationDecl *Specialization = nullptr;
7830 // Check whether we can declare a class template specialization in
7831 // the current scope.
7832 if (TUK != TUK_Friend &&
7833 CheckTemplateSpecializationScope(*this, ClassTemplate, PrevDecl,
7835 isPartialSpecialization))
7838 // The canonical type
7840 if (isPartialSpecialization) {
7841 // Build the canonical type that describes the converted template
7842 // arguments of the class template partial specialization.
7843 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7844 CanonType = Context.getTemplateSpecializationType(CanonTemplate,
7847 if (Context.hasSameType(CanonType,
7848 ClassTemplate->getInjectedClassNameSpecialization())) {
7849 // C++ [temp.class.spec]p9b3:
7851 // -- The argument list of the specialization shall not be identical
7852 // to the implicit argument list of the primary template.
7854 // This rule has since been removed, because it's redundant given DR1495,
7855 // but we keep it because it produces better diagnostics and recovery.
7856 Diag(TemplateNameLoc, diag::err_partial_spec_args_match_primary_template)
7857 << /*class template*/0 << (TUK == TUK_Definition)
7858 << FixItHint::CreateRemoval(SourceRange(LAngleLoc, RAngleLoc));
7859 return CheckClassTemplate(S, TagSpec, TUK, KWLoc, SS,
7860 ClassTemplate->getIdentifier(),
7864 AS_none, /*ModulePrivateLoc=*/SourceLocation(),
7865 /*FriendLoc*/SourceLocation(),
7866 TemplateParameterLists.size() - 1,
7867 TemplateParameterLists.data());
7870 // Create a new class template partial specialization declaration node.
7871 ClassTemplatePartialSpecializationDecl *PrevPartial
7872 = cast_or_null<ClassTemplatePartialSpecializationDecl>(PrevDecl);
7873 ClassTemplatePartialSpecializationDecl *Partial
7874 = ClassTemplatePartialSpecializationDecl::Create(Context, Kind,
7875 ClassTemplate->getDeclContext(),
7876 KWLoc, TemplateNameLoc,
7883 SetNestedNameSpecifier(*this, Partial, SS);
7884 if (TemplateParameterLists.size() > 1 && SS.isSet()) {
7885 Partial->setTemplateParameterListsInfo(
7886 Context, TemplateParameterLists.drop_back(1));
7890 ClassTemplate->AddPartialSpecialization(Partial, InsertPos);
7891 Specialization = Partial;
7893 // If we are providing an explicit specialization of a member class
7894 // template specialization, make a note of that.
7895 if (PrevPartial && PrevPartial->getInstantiatedFromMember())
7896 PrevPartial->setMemberSpecialization();
7898 CheckTemplatePartialSpecialization(Partial);
7900 // Create a new class template specialization declaration node for
7901 // this explicit specialization or friend declaration.
7903 = ClassTemplateSpecializationDecl::Create(Context, Kind,
7904 ClassTemplate->getDeclContext(),
7905 KWLoc, TemplateNameLoc,
7909 SetNestedNameSpecifier(*this, Specialization, SS);
7910 if (TemplateParameterLists.size() > 0) {
7911 Specialization->setTemplateParameterListsInfo(Context,
7912 TemplateParameterLists);
7916 ClassTemplate->AddSpecialization(Specialization, InsertPos);
7918 if (CurContext->isDependentContext()) {
7919 TemplateName CanonTemplate = Context.getCanonicalTemplateName(Name);
7920 CanonType = Context.getTemplateSpecializationType(
7921 CanonTemplate, Converted);
7923 CanonType = Context.getTypeDeclType(Specialization);
7927 // C++ [temp.expl.spec]p6:
7928 // If a template, a member template or the member of a class template is
7929 // explicitly specialized then that specialization shall be declared
7930 // before the first use of that specialization that would cause an implicit
7931 // instantiation to take place, in every translation unit in which such a
7932 // use occurs; no diagnostic is required.
7933 if (PrevDecl && PrevDecl->getPointOfInstantiation().isValid()) {
7935 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
7936 // Is there any previous explicit specialization declaration?
7937 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
7944 SourceRange Range(TemplateNameLoc, RAngleLoc);
7945 Diag(TemplateNameLoc, diag::err_specialization_after_instantiation)
7946 << Context.getTypeDeclType(Specialization) << Range;
7948 Diag(PrevDecl->getPointOfInstantiation(),
7949 diag::note_instantiation_required_here)
7950 << (PrevDecl->getTemplateSpecializationKind()
7951 != TSK_ImplicitInstantiation);
7956 // If this is not a friend, note that this is an explicit specialization.
7957 if (TUK != TUK_Friend)
7958 Specialization->setSpecializationKind(TSK_ExplicitSpecialization);
7960 // Check that this isn't a redefinition of this specialization.
7961 if (TUK == TUK_Definition) {
7962 RecordDecl *Def = Specialization->getDefinition();
7963 NamedDecl *Hidden = nullptr;
7964 if (Def && SkipBody && !hasVisibleDefinition(Def, &Hidden)) {
7965 SkipBody->ShouldSkip = true;
7966 SkipBody->Previous = Def;
7967 makeMergedDefinitionVisible(Hidden);
7969 SourceRange Range(TemplateNameLoc, RAngleLoc);
7970 Diag(TemplateNameLoc, diag::err_redefinition) << Specialization << Range;
7971 Diag(Def->getLocation(), diag::note_previous_definition);
7972 Specialization->setInvalidDecl();
7977 ProcessDeclAttributeList(S, Specialization, Attr);
7979 // Add alignment attributes if necessary; these attributes are checked when
7980 // the ASTContext lays out the structure.
7981 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip)) {
7982 AddAlignmentAttributesForRecord(Specialization);
7983 AddMsStructLayoutForRecord(Specialization);
7986 if (ModulePrivateLoc.isValid())
7987 Diag(Specialization->getLocation(), diag::err_module_private_specialization)
7988 << (isPartialSpecialization? 1 : 0)
7989 << FixItHint::CreateRemoval(ModulePrivateLoc);
7991 // Build the fully-sugared type for this class template
7992 // specialization as the user wrote in the specialization
7993 // itself. This means that we'll pretty-print the type retrieved
7994 // from the specialization's declaration the way that the user
7995 // actually wrote the specialization, rather than formatting the
7996 // name based on the "canonical" representation used to store the
7997 // template arguments in the specialization.
7998 TypeSourceInfo *WrittenTy
7999 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
8000 TemplateArgs, CanonType);
8001 if (TUK != TUK_Friend) {
8002 Specialization->setTypeAsWritten(WrittenTy);
8003 Specialization->setTemplateKeywordLoc(TemplateKWLoc);
8006 // C++ [temp.expl.spec]p9:
8007 // A template explicit specialization is in the scope of the
8008 // namespace in which the template was defined.
8010 // We actually implement this paragraph where we set the semantic
8011 // context (in the creation of the ClassTemplateSpecializationDecl),
8012 // but we also maintain the lexical context where the actual
8013 // definition occurs.
8014 Specialization->setLexicalDeclContext(CurContext);
8016 // We may be starting the definition of this specialization.
8017 if (TUK == TUK_Definition && (!SkipBody || !SkipBody->ShouldSkip))
8018 Specialization->startDefinition();
8020 if (TUK == TUK_Friend) {
8021 FriendDecl *Friend = FriendDecl::Create(Context, CurContext,
8025 Friend->setAccess(AS_public);
8026 CurContext->addDecl(Friend);
8028 // Add the specialization into its lexical context, so that it can
8029 // be seen when iterating through the list of declarations in that
8030 // context. However, specializations are not found by name lookup.
8031 CurContext->addDecl(Specialization);
8034 if (SkipBody && SkipBody->ShouldSkip)
8035 return SkipBody->Previous;
8037 return Specialization;
8040 Decl *Sema::ActOnTemplateDeclarator(Scope *S,
8041 MultiTemplateParamsArg TemplateParameterLists,
8043 Decl *NewDecl = HandleDeclarator(S, D, TemplateParameterLists);
8044 ActOnDocumentableDecl(NewDecl);
8048 Decl *Sema::ActOnConceptDefinition(Scope *S,
8049 MultiTemplateParamsArg TemplateParameterLists,
8050 IdentifierInfo *Name, SourceLocation NameLoc,
8051 Expr *ConstraintExpr) {
8052 DeclContext *DC = CurContext;
8054 if (!DC->getRedeclContext()->isFileContext()) {
8056 diag::err_concept_decls_may_only_appear_in_global_namespace_scope);
8060 if (TemplateParameterLists.size() > 1) {
8061 Diag(NameLoc, diag::err_concept_extra_headers);
8065 if (TemplateParameterLists.front()->size() == 0) {
8066 Diag(NameLoc, diag::err_concept_no_parameters);
8070 ConceptDecl *NewDecl = ConceptDecl::Create(Context, DC, NameLoc, Name,
8071 TemplateParameterLists.front(),
8074 if (NewDecl->hasAssociatedConstraints()) {
8075 // C++2a [temp.concept]p4:
8076 // A concept shall not have associated constraints.
8077 Diag(NameLoc, diag::err_concept_no_associated_constraints);
8078 NewDecl->setInvalidDecl();
8081 // Check for conflicting previous declaration.
8082 DeclarationNameInfo NameInfo(NewDecl->getDeclName(), NameLoc);
8083 LookupResult Previous(*this, NameInfo, LookupOrdinaryName,
8084 ForVisibleRedeclaration);
8085 LookupName(Previous, S);
8087 FilterLookupForScope(Previous, DC, S, /*ConsiderLinkage=*/false,
8088 /*AllowInlineNamespace*/false);
8089 if (!Previous.empty()) {
8090 auto *Old = Previous.getRepresentativeDecl();
8091 Diag(NameLoc, isa<ConceptDecl>(Old) ? diag::err_redefinition :
8092 diag::err_redefinition_different_kind) << NewDecl->getDeclName();
8093 Diag(Old->getLocation(), diag::note_previous_definition);
8096 ActOnDocumentableDecl(NewDecl);
8097 PushOnScopeChains(NewDecl, S);
8101 /// \brief Strips various properties off an implicit instantiation
8102 /// that has just been explicitly specialized.
8103 static void StripImplicitInstantiation(NamedDecl *D) {
8104 D->dropAttr<DLLImportAttr>();
8105 D->dropAttr<DLLExportAttr>();
8107 if (FunctionDecl *FD = dyn_cast<FunctionDecl>(D))
8108 FD->setInlineSpecified(false);
8111 /// Compute the diagnostic location for an explicit instantiation
8112 // declaration or definition.
8113 static SourceLocation DiagLocForExplicitInstantiation(
8114 NamedDecl* D, SourceLocation PointOfInstantiation) {
8115 // Explicit instantiations following a specialization have no effect and
8116 // hence no PointOfInstantiation. In that case, walk decl backwards
8117 // until a valid name loc is found.
8118 SourceLocation PrevDiagLoc = PointOfInstantiation;
8119 for (Decl *Prev = D; Prev && !PrevDiagLoc.isValid();
8120 Prev = Prev->getPreviousDecl()) {
8121 PrevDiagLoc = Prev->getLocation();
8123 assert(PrevDiagLoc.isValid() &&
8124 "Explicit instantiation without point of instantiation?");
8128 /// Diagnose cases where we have an explicit template specialization
8129 /// before/after an explicit template instantiation, producing diagnostics
8130 /// for those cases where they are required and determining whether the
8131 /// new specialization/instantiation will have any effect.
8133 /// \param NewLoc the location of the new explicit specialization or
8136 /// \param NewTSK the kind of the new explicit specialization or instantiation.
8138 /// \param PrevDecl the previous declaration of the entity.
8140 /// \param PrevTSK the kind of the old explicit specialization or instantiatin.
8142 /// \param PrevPointOfInstantiation if valid, indicates where the previus
8143 /// declaration was instantiated (either implicitly or explicitly).
8145 /// \param HasNoEffect will be set to true to indicate that the new
8146 /// specialization or instantiation has no effect and should be ignored.
8148 /// \returns true if there was an error that should prevent the introduction of
8149 /// the new declaration into the AST, false otherwise.
8151 Sema::CheckSpecializationInstantiationRedecl(SourceLocation NewLoc,
8152 TemplateSpecializationKind NewTSK,
8153 NamedDecl *PrevDecl,
8154 TemplateSpecializationKind PrevTSK,
8155 SourceLocation PrevPointOfInstantiation,
8156 bool &HasNoEffect) {
8157 HasNoEffect = false;
8160 case TSK_Undeclared:
8161 case TSK_ImplicitInstantiation:
8163 (PrevTSK == TSK_Undeclared || PrevTSK == TSK_ImplicitInstantiation) &&
8164 "previous declaration must be implicit!");
8167 case TSK_ExplicitSpecialization:
8169 case TSK_Undeclared:
8170 case TSK_ExplicitSpecialization:
8171 // Okay, we're just specializing something that is either already
8172 // explicitly specialized or has merely been mentioned without any
8176 case TSK_ImplicitInstantiation:
8177 if (PrevPointOfInstantiation.isInvalid()) {
8178 // The declaration itself has not actually been instantiated, so it is
8179 // still okay to specialize it.
8180 StripImplicitInstantiation(PrevDecl);
8186 case TSK_ExplicitInstantiationDeclaration:
8187 case TSK_ExplicitInstantiationDefinition:
8188 assert((PrevTSK == TSK_ImplicitInstantiation ||
8189 PrevPointOfInstantiation.isValid()) &&
8190 "Explicit instantiation without point of instantiation?");
8192 // C++ [temp.expl.spec]p6:
8193 // If a template, a member template or the member of a class template
8194 // is explicitly specialized then that specialization shall be declared
8195 // before the first use of that specialization that would cause an
8196 // implicit instantiation to take place, in every translation unit in
8197 // which such a use occurs; no diagnostic is required.
8198 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8199 // Is there any previous explicit specialization declaration?
8200 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization)
8204 Diag(NewLoc, diag::err_specialization_after_instantiation)
8206 Diag(PrevPointOfInstantiation, diag::note_instantiation_required_here)
8207 << (PrevTSK != TSK_ImplicitInstantiation);
8211 llvm_unreachable("The switch over PrevTSK must be exhaustive.");
8213 case TSK_ExplicitInstantiationDeclaration:
8215 case TSK_ExplicitInstantiationDeclaration:
8216 // This explicit instantiation declaration is redundant (that's okay).
8220 case TSK_Undeclared:
8221 case TSK_ImplicitInstantiation:
8222 // We're explicitly instantiating something that may have already been
8223 // implicitly instantiated; that's fine.
8226 case TSK_ExplicitSpecialization:
8227 // C++0x [temp.explicit]p4:
8228 // For a given set of template parameters, if an explicit instantiation
8229 // of a template appears after a declaration of an explicit
8230 // specialization for that template, the explicit instantiation has no
8235 case TSK_ExplicitInstantiationDefinition:
8236 // C++0x [temp.explicit]p10:
8237 // If an entity is the subject of both an explicit instantiation
8238 // declaration and an explicit instantiation definition in the same
8239 // translation unit, the definition shall follow the declaration.
8241 diag::err_explicit_instantiation_declaration_after_definition);
8243 // Explicit instantiations following a specialization have no effect and
8244 // hence no PrevPointOfInstantiation. In that case, walk decl backwards
8245 // until a valid name loc is found.
8246 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8247 diag::note_explicit_instantiation_definition_here);
8251 llvm_unreachable("Unexpected TemplateSpecializationKind!");
8253 case TSK_ExplicitInstantiationDefinition:
8255 case TSK_Undeclared:
8256 case TSK_ImplicitInstantiation:
8257 // We're explicitly instantiating something that may have already been
8258 // implicitly instantiated; that's fine.
8261 case TSK_ExplicitSpecialization:
8262 // C++ DR 259, C++0x [temp.explicit]p4:
8263 // For a given set of template parameters, if an explicit
8264 // instantiation of a template appears after a declaration of
8265 // an explicit specialization for that template, the explicit
8266 // instantiation has no effect.
8267 Diag(NewLoc, diag::warn_explicit_instantiation_after_specialization)
8269 Diag(PrevDecl->getLocation(),
8270 diag::note_previous_template_specialization);
8274 case TSK_ExplicitInstantiationDeclaration:
8275 // We're explicitly instantiating a definition for something for which we
8276 // were previously asked to suppress instantiations. That's fine.
8278 // C++0x [temp.explicit]p4:
8279 // For a given set of template parameters, if an explicit instantiation
8280 // of a template appears after a declaration of an explicit
8281 // specialization for that template, the explicit instantiation has no
8283 for (Decl *Prev = PrevDecl; Prev; Prev = Prev->getPreviousDecl()) {
8284 // Is there any previous explicit specialization declaration?
8285 if (getTemplateSpecializationKind(Prev) == TSK_ExplicitSpecialization) {
8293 case TSK_ExplicitInstantiationDefinition:
8294 // C++0x [temp.spec]p5:
8295 // For a given template and a given set of template-arguments,
8296 // - an explicit instantiation definition shall appear at most once
8299 // MSVCCompat: MSVC silently ignores duplicate explicit instantiations.
8300 Diag(NewLoc, (getLangOpts().MSVCCompat)
8301 ? diag::ext_explicit_instantiation_duplicate
8302 : diag::err_explicit_instantiation_duplicate)
8304 Diag(DiagLocForExplicitInstantiation(PrevDecl, PrevPointOfInstantiation),
8305 diag::note_previous_explicit_instantiation);
8311 llvm_unreachable("Missing specialization/instantiation case?");
8314 /// Perform semantic analysis for the given dependent function
8315 /// template specialization.
8317 /// The only possible way to get a dependent function template specialization
8318 /// is with a friend declaration, like so:
8321 /// template \<class T> void foo(T);
8322 /// template \<class T> class A {
8323 /// friend void foo<>(T);
8327 /// There really isn't any useful analysis we can do here, so we
8328 /// just store the information.
8330 Sema::CheckDependentFunctionTemplateSpecialization(FunctionDecl *FD,
8331 const TemplateArgumentListInfo &ExplicitTemplateArgs,
8332 LookupResult &Previous) {
8333 // Remove anything from Previous that isn't a function template in
8334 // the correct context.
8335 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8336 LookupResult::Filter F = Previous.makeFilter();
8337 enum DiscardReason { NotAFunctionTemplate, NotAMemberOfEnclosing };
8338 SmallVector<std::pair<DiscardReason, Decl *>, 8> DiscardedCandidates;
8339 while (F.hasNext()) {
8340 NamedDecl *D = F.next()->getUnderlyingDecl();
8341 if (!isa<FunctionTemplateDecl>(D)) {
8343 DiscardedCandidates.push_back(std::make_pair(NotAFunctionTemplate, D));
8347 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8348 D->getDeclContext()->getRedeclContext())) {
8350 DiscardedCandidates.push_back(std::make_pair(NotAMemberOfEnclosing, D));
8356 if (Previous.empty()) {
8357 Diag(FD->getLocation(),
8358 diag::err_dependent_function_template_spec_no_match);
8359 for (auto &P : DiscardedCandidates)
8360 Diag(P.second->getLocation(),
8361 diag::note_dependent_function_template_spec_discard_reason)
8366 FD->setDependentTemplateSpecialization(Context, Previous.asUnresolvedSet(),
8367 ExplicitTemplateArgs);
8371 /// Perform semantic analysis for the given function template
8374 /// This routine performs all of the semantic analysis required for an
8375 /// explicit function template specialization. On successful completion,
8376 /// the function declaration \p FD will become a function template
8379 /// \param FD the function declaration, which will be updated to become a
8380 /// function template specialization.
8382 /// \param ExplicitTemplateArgs the explicitly-provided template arguments,
8383 /// if any. Note that this may be valid info even when 0 arguments are
8384 /// explicitly provided as in, e.g., \c void sort<>(char*, char*);
8385 /// as it anyway contains info on the angle brackets locations.
8387 /// \param Previous the set of declarations that may be specialized by
8388 /// this function specialization.
8390 /// \param QualifiedFriend whether this is a lookup for a qualified friend
8391 /// declaration with no explicit template argument list that might be
8392 /// befriending a function template specialization.
8393 bool Sema::CheckFunctionTemplateSpecialization(
8394 FunctionDecl *FD, TemplateArgumentListInfo *ExplicitTemplateArgs,
8395 LookupResult &Previous, bool QualifiedFriend) {
8396 // The set of function template specializations that could match this
8397 // explicit function template specialization.
8398 UnresolvedSet<8> Candidates;
8399 TemplateSpecCandidateSet FailedCandidates(FD->getLocation(),
8400 /*ForTakingAddress=*/false);
8402 llvm::SmallDenseMap<FunctionDecl *, TemplateArgumentListInfo, 8>
8403 ConvertedTemplateArgs;
8405 DeclContext *FDLookupContext = FD->getDeclContext()->getRedeclContext();
8406 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8408 NamedDecl *Ovl = (*I)->getUnderlyingDecl();
8409 if (FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Ovl)) {
8410 // Only consider templates found within the same semantic lookup scope as
8412 if (!FDLookupContext->InEnclosingNamespaceSetOf(
8413 Ovl->getDeclContext()->getRedeclContext()))
8416 // When matching a constexpr member function template specialization
8417 // against the primary template, we don't yet know whether the
8418 // specialization has an implicit 'const' (because we don't know whether
8419 // it will be a static member function until we know which template it
8420 // specializes), so adjust it now assuming it specializes this template.
8421 QualType FT = FD->getType();
8422 if (FD->isConstexpr()) {
8423 CXXMethodDecl *OldMD =
8424 dyn_cast<CXXMethodDecl>(FunTmpl->getTemplatedDecl());
8425 if (OldMD && OldMD->isConst()) {
8426 const FunctionProtoType *FPT = FT->castAs<FunctionProtoType>();
8427 FunctionProtoType::ExtProtoInfo EPI = FPT->getExtProtoInfo();
8428 EPI.TypeQuals.addConst();
8429 FT = Context.getFunctionType(FPT->getReturnType(),
8430 FPT->getParamTypes(), EPI);
8434 TemplateArgumentListInfo Args;
8435 if (ExplicitTemplateArgs)
8436 Args = *ExplicitTemplateArgs;
8438 // C++ [temp.expl.spec]p11:
8439 // A trailing template-argument can be left unspecified in the
8440 // template-id naming an explicit function template specialization
8441 // provided it can be deduced from the function argument type.
8442 // Perform template argument deduction to determine whether we may be
8443 // specializing this template.
8444 // FIXME: It is somewhat wasteful to build
8445 TemplateDeductionInfo Info(FailedCandidates.getLocation());
8446 FunctionDecl *Specialization = nullptr;
8447 if (TemplateDeductionResult TDK = DeduceTemplateArguments(
8448 cast<FunctionTemplateDecl>(FunTmpl->getFirstDecl()),
8449 ExplicitTemplateArgs ? &Args : nullptr, FT, Specialization,
8451 // Template argument deduction failed; record why it failed, so
8452 // that we can provide nifty diagnostics.
8453 FailedCandidates.addCandidate().set(
8454 I.getPair(), FunTmpl->getTemplatedDecl(),
8455 MakeDeductionFailureInfo(Context, TDK, Info));
8460 // Target attributes are part of the cuda function signature, so
8461 // the deduced template's cuda target must match that of the
8462 // specialization. Given that C++ template deduction does not
8463 // take target attributes into account, we reject candidates
8464 // here that have a different target.
8465 if (LangOpts.CUDA &&
8466 IdentifyCUDATarget(Specialization,
8467 /* IgnoreImplicitHDAttr = */ true) !=
8468 IdentifyCUDATarget(FD, /* IgnoreImplicitHDAttr = */ true)) {
8469 FailedCandidates.addCandidate().set(
8470 I.getPair(), FunTmpl->getTemplatedDecl(),
8471 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
8475 // Record this candidate.
8476 if (ExplicitTemplateArgs)
8477 ConvertedTemplateArgs[Specialization] = std::move(Args);
8478 Candidates.addDecl(Specialization, I.getAccess());
8482 // For a qualified friend declaration (with no explicit marker to indicate
8483 // that a template specialization was intended), note all (template and
8484 // non-template) candidates.
8485 if (QualifiedFriend && Candidates.empty()) {
8486 Diag(FD->getLocation(), diag::err_qualified_friend_no_match)
8487 << FD->getDeclName() << FDLookupContext;
8488 // FIXME: We should form a single candidate list and diagnose all
8489 // candidates at once, to get proper sorting and limiting.
8490 for (auto *OldND : Previous) {
8491 if (auto *OldFD = dyn_cast<FunctionDecl>(OldND->getUnderlyingDecl()))
8492 NoteOverloadCandidate(OldND, OldFD, CRK_None, FD->getType(), false);
8494 FailedCandidates.NoteCandidates(*this, FD->getLocation());
8498 // Find the most specialized function template.
8499 UnresolvedSetIterator Result = getMostSpecialized(
8500 Candidates.begin(), Candidates.end(), FailedCandidates, FD->getLocation(),
8501 PDiag(diag::err_function_template_spec_no_match) << FD->getDeclName(),
8502 PDiag(diag::err_function_template_spec_ambiguous)
8503 << FD->getDeclName() << (ExplicitTemplateArgs != nullptr),
8504 PDiag(diag::note_function_template_spec_matched));
8506 if (Result == Candidates.end())
8509 // Ignore access information; it doesn't figure into redeclaration checking.
8510 FunctionDecl *Specialization = cast<FunctionDecl>(*Result);
8512 FunctionTemplateSpecializationInfo *SpecInfo
8513 = Specialization->getTemplateSpecializationInfo();
8514 assert(SpecInfo && "Function template specialization info missing?");
8516 // Note: do not overwrite location info if previous template
8517 // specialization kind was explicit.
8518 TemplateSpecializationKind TSK = SpecInfo->getTemplateSpecializationKind();
8519 if (TSK == TSK_Undeclared || TSK == TSK_ImplicitInstantiation) {
8520 Specialization->setLocation(FD->getLocation());
8521 Specialization->setLexicalDeclContext(FD->getLexicalDeclContext());
8522 // C++11 [dcl.constexpr]p1: An explicit specialization of a constexpr
8523 // function can differ from the template declaration with respect to
8524 // the constexpr specifier.
8525 // FIXME: We need an update record for this AST mutation.
8526 // FIXME: What if there are multiple such prior declarations (for instance,
8527 // from different modules)?
8528 Specialization->setConstexprKind(FD->getConstexprKind());
8531 // FIXME: Check if the prior specialization has a point of instantiation.
8532 // If so, we have run afoul of .
8534 // If this is a friend declaration, then we're not really declaring
8535 // an explicit specialization.
8536 bool isFriend = (FD->getFriendObjectKind() != Decl::FOK_None);
8538 // Check the scope of this explicit specialization.
8540 CheckTemplateSpecializationScope(*this,
8541 Specialization->getPrimaryTemplate(),
8542 Specialization, FD->getLocation(),
8546 // C++ [temp.expl.spec]p6:
8547 // If a template, a member template or the member of a class template is
8548 // explicitly specialized then that specialization shall be declared
8549 // before the first use of that specialization that would cause an implicit
8550 // instantiation to take place, in every translation unit in which such a
8551 // use occurs; no diagnostic is required.
8552 bool HasNoEffect = false;
8554 CheckSpecializationInstantiationRedecl(FD->getLocation(),
8555 TSK_ExplicitSpecialization,
8557 SpecInfo->getTemplateSpecializationKind(),
8558 SpecInfo->getPointOfInstantiation(),
8562 // Mark the prior declaration as an explicit specialization, so that later
8563 // clients know that this is an explicit specialization.
8565 // Since explicit specializations do not inherit '=delete' from their
8566 // primary function template - check if the 'specialization' that was
8567 // implicitly generated (during template argument deduction for partial
8568 // ordering) from the most specialized of all the function templates that
8569 // 'FD' could have been specializing, has a 'deleted' definition. If so,
8570 // first check that it was implicitly generated during template argument
8571 // deduction by making sure it wasn't referenced, and then reset the deleted
8572 // flag to not-deleted, so that we can inherit that information from 'FD'.
8573 if (Specialization->isDeleted() && !SpecInfo->isExplicitSpecialization() &&
8574 !Specialization->getCanonicalDecl()->isReferenced()) {
8575 // FIXME: This assert will not hold in the presence of modules.
8577 Specialization->getCanonicalDecl() == Specialization &&
8578 "This must be the only existing declaration of this specialization");
8579 // FIXME: We need an update record for this AST mutation.
8580 Specialization->setDeletedAsWritten(false);
8582 // FIXME: We need an update record for this AST mutation.
8583 SpecInfo->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8584 MarkUnusedFileScopedDecl(Specialization);
8587 // Turn the given function declaration into a function template
8588 // specialization, with the template arguments from the previous
8590 // Take copies of (semantic and syntactic) template argument lists.
8591 const TemplateArgumentList* TemplArgs = new (Context)
8592 TemplateArgumentList(Specialization->getTemplateSpecializationArgs());
8593 FD->setFunctionTemplateSpecialization(
8594 Specialization->getPrimaryTemplate(), TemplArgs, /*InsertPos=*/nullptr,
8595 SpecInfo->getTemplateSpecializationKind(),
8596 ExplicitTemplateArgs ? &ConvertedTemplateArgs[Specialization] : nullptr);
8598 // A function template specialization inherits the target attributes
8599 // of its template. (We require the attributes explicitly in the
8600 // code to match, but a template may have implicit attributes by
8601 // virtue e.g. of being constexpr, and it passes these implicit
8602 // attributes on to its specializations.)
8604 inheritCUDATargetAttrs(FD, *Specialization->getPrimaryTemplate());
8606 // The "previous declaration" for this function template specialization is
8607 // the prior function template specialization.
8609 Previous.addDecl(Specialization);
8613 /// Perform semantic analysis for the given non-template member
8616 /// This routine performs all of the semantic analysis required for an
8617 /// explicit member function specialization. On successful completion,
8618 /// the function declaration \p FD will become a member function
8621 /// \param Member the member declaration, which will be updated to become a
8624 /// \param Previous the set of declarations, one of which may be specialized
8625 /// by this function specialization; the set will be modified to contain the
8626 /// redeclared member.
8628 Sema::CheckMemberSpecialization(NamedDecl *Member, LookupResult &Previous) {
8629 assert(!isa<TemplateDecl>(Member) && "Only for non-template members");
8631 // Try to find the member we are instantiating.
8632 NamedDecl *FoundInstantiation = nullptr;
8633 NamedDecl *Instantiation = nullptr;
8634 NamedDecl *InstantiatedFrom = nullptr;
8635 MemberSpecializationInfo *MSInfo = nullptr;
8637 if (Previous.empty()) {
8638 // Nowhere to look anyway.
8639 } else if (FunctionDecl *Function = dyn_cast<FunctionDecl>(Member)) {
8640 for (LookupResult::iterator I = Previous.begin(), E = Previous.end();
8642 NamedDecl *D = (*I)->getUnderlyingDecl();
8643 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(D)) {
8644 QualType Adjusted = Function->getType();
8645 if (!hasExplicitCallingConv(Adjusted))
8646 Adjusted = adjustCCAndNoReturn(Adjusted, Method->getType());
8647 // This doesn't handle deduced return types, but both function
8648 // declarations should be undeduced at this point.
8649 if (Context.hasSameType(Adjusted, Method->getType())) {
8650 FoundInstantiation = *I;
8651 Instantiation = Method;
8652 InstantiatedFrom = Method->getInstantiatedFromMemberFunction();
8653 MSInfo = Method->getMemberSpecializationInfo();
8658 } else if (isa<VarDecl>(Member)) {
8660 if (Previous.isSingleResult() &&
8661 (PrevVar = dyn_cast<VarDecl>(Previous.getFoundDecl())))
8662 if (PrevVar->isStaticDataMember()) {
8663 FoundInstantiation = Previous.getRepresentativeDecl();
8664 Instantiation = PrevVar;
8665 InstantiatedFrom = PrevVar->getInstantiatedFromStaticDataMember();
8666 MSInfo = PrevVar->getMemberSpecializationInfo();
8668 } else if (isa<RecordDecl>(Member)) {
8669 CXXRecordDecl *PrevRecord;
8670 if (Previous.isSingleResult() &&
8671 (PrevRecord = dyn_cast<CXXRecordDecl>(Previous.getFoundDecl()))) {
8672 FoundInstantiation = Previous.getRepresentativeDecl();
8673 Instantiation = PrevRecord;
8674 InstantiatedFrom = PrevRecord->getInstantiatedFromMemberClass();
8675 MSInfo = PrevRecord->getMemberSpecializationInfo();
8677 } else if (isa<EnumDecl>(Member)) {
8679 if (Previous.isSingleResult() &&
8680 (PrevEnum = dyn_cast<EnumDecl>(Previous.getFoundDecl()))) {
8681 FoundInstantiation = Previous.getRepresentativeDecl();
8682 Instantiation = PrevEnum;
8683 InstantiatedFrom = PrevEnum->getInstantiatedFromMemberEnum();
8684 MSInfo = PrevEnum->getMemberSpecializationInfo();
8688 if (!Instantiation) {
8689 // There is no previous declaration that matches. Since member
8690 // specializations are always out-of-line, the caller will complain about
8691 // this mismatch later.
8695 // A member specialization in a friend declaration isn't really declaring
8696 // an explicit specialization, just identifying a specific (possibly implicit)
8697 // specialization. Don't change the template specialization kind.
8699 // FIXME: Is this really valid? Other compilers reject.
8700 if (Member->getFriendObjectKind() != Decl::FOK_None) {
8701 // Preserve instantiation information.
8702 if (InstantiatedFrom && isa<CXXMethodDecl>(Member)) {
8703 cast<CXXMethodDecl>(Member)->setInstantiationOfMemberFunction(
8704 cast<CXXMethodDecl>(InstantiatedFrom),
8705 cast<CXXMethodDecl>(Instantiation)->getTemplateSpecializationKind());
8706 } else if (InstantiatedFrom && isa<CXXRecordDecl>(Member)) {
8707 cast<CXXRecordDecl>(Member)->setInstantiationOfMemberClass(
8708 cast<CXXRecordDecl>(InstantiatedFrom),
8709 cast<CXXRecordDecl>(Instantiation)->getTemplateSpecializationKind());
8713 Previous.addDecl(FoundInstantiation);
8717 // Make sure that this is a specialization of a member.
8718 if (!InstantiatedFrom) {
8719 Diag(Member->getLocation(), diag::err_spec_member_not_instantiated)
8721 Diag(Instantiation->getLocation(), diag::note_specialized_decl);
8725 // C++ [temp.expl.spec]p6:
8726 // If a template, a member template or the member of a class template is
8727 // explicitly specialized then that specialization shall be declared
8728 // before the first use of that specialization that would cause an implicit
8729 // instantiation to take place, in every translation unit in which such a
8730 // use occurs; no diagnostic is required.
8731 assert(MSInfo && "Member specialization info missing?");
8733 bool HasNoEffect = false;
8734 if (CheckSpecializationInstantiationRedecl(Member->getLocation(),
8735 TSK_ExplicitSpecialization,
8737 MSInfo->getTemplateSpecializationKind(),
8738 MSInfo->getPointOfInstantiation(),
8742 // Check the scope of this explicit specialization.
8743 if (CheckTemplateSpecializationScope(*this,
8745 Instantiation, Member->getLocation(),
8749 // Note that this member specialization is an "instantiation of" the
8750 // corresponding member of the original template.
8751 if (auto *MemberFunction = dyn_cast<FunctionDecl>(Member)) {
8752 FunctionDecl *InstantiationFunction = cast<FunctionDecl>(Instantiation);
8753 if (InstantiationFunction->getTemplateSpecializationKind() ==
8754 TSK_ImplicitInstantiation) {
8755 // Explicit specializations of member functions of class templates do not
8756 // inherit '=delete' from the member function they are specializing.
8757 if (InstantiationFunction->isDeleted()) {
8758 // FIXME: This assert will not hold in the presence of modules.
8759 assert(InstantiationFunction->getCanonicalDecl() ==
8760 InstantiationFunction);
8761 // FIXME: We need an update record for this AST mutation.
8762 InstantiationFunction->setDeletedAsWritten(false);
8766 MemberFunction->setInstantiationOfMemberFunction(
8767 cast<CXXMethodDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8768 } else if (auto *MemberVar = dyn_cast<VarDecl>(Member)) {
8769 MemberVar->setInstantiationOfStaticDataMember(
8770 cast<VarDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8771 } else if (auto *MemberClass = dyn_cast<CXXRecordDecl>(Member)) {
8772 MemberClass->setInstantiationOfMemberClass(
8773 cast<CXXRecordDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8774 } else if (auto *MemberEnum = dyn_cast<EnumDecl>(Member)) {
8775 MemberEnum->setInstantiationOfMemberEnum(
8776 cast<EnumDecl>(InstantiatedFrom), TSK_ExplicitSpecialization);
8778 llvm_unreachable("unknown member specialization kind");
8781 // Save the caller the trouble of having to figure out which declaration
8782 // this specialization matches.
8784 Previous.addDecl(FoundInstantiation);
8788 /// Complete the explicit specialization of a member of a class template by
8789 /// updating the instantiated member to be marked as an explicit specialization.
8791 /// \param OrigD The member declaration instantiated from the template.
8792 /// \param Loc The location of the explicit specialization of the member.
8793 template<typename DeclT>
8794 static void completeMemberSpecializationImpl(Sema &S, DeclT *OrigD,
8795 SourceLocation Loc) {
8796 if (OrigD->getTemplateSpecializationKind() != TSK_ImplicitInstantiation)
8799 // FIXME: Inform AST mutation listeners of this AST mutation.
8800 // FIXME: If there are multiple in-class declarations of the member (from
8801 // multiple modules, or a declaration and later definition of a member type),
8802 // should we update all of them?
8803 OrigD->setTemplateSpecializationKind(TSK_ExplicitSpecialization);
8804 OrigD->setLocation(Loc);
8807 void Sema::CompleteMemberSpecialization(NamedDecl *Member,
8808 LookupResult &Previous) {
8809 NamedDecl *Instantiation = cast<NamedDecl>(Member->getCanonicalDecl());
8810 if (Instantiation == Member)
8813 if (auto *Function = dyn_cast<CXXMethodDecl>(Instantiation))
8814 completeMemberSpecializationImpl(*this, Function, Member->getLocation());
8815 else if (auto *Var = dyn_cast<VarDecl>(Instantiation))
8816 completeMemberSpecializationImpl(*this, Var, Member->getLocation());
8817 else if (auto *Record = dyn_cast<CXXRecordDecl>(Instantiation))
8818 completeMemberSpecializationImpl(*this, Record, Member->getLocation());
8819 else if (auto *Enum = dyn_cast<EnumDecl>(Instantiation))
8820 completeMemberSpecializationImpl(*this, Enum, Member->getLocation());
8822 llvm_unreachable("unknown member specialization kind");
8825 /// Check the scope of an explicit instantiation.
8827 /// \returns true if a serious error occurs, false otherwise.
8828 static bool CheckExplicitInstantiationScope(Sema &S, NamedDecl *D,
8829 SourceLocation InstLoc,
8830 bool WasQualifiedName) {
8831 DeclContext *OrigContext= D->getDeclContext()->getEnclosingNamespaceContext();
8832 DeclContext *CurContext = S.CurContext->getRedeclContext();
8834 if (CurContext->isRecord()) {
8835 S.Diag(InstLoc, diag::err_explicit_instantiation_in_class)
8840 // C++11 [temp.explicit]p3:
8841 // An explicit instantiation shall appear in an enclosing namespace of its
8842 // template. If the name declared in the explicit instantiation is an
8843 // unqualified name, the explicit instantiation shall appear in the
8844 // namespace where its template is declared or, if that namespace is inline
8845 // (7.3.1), any namespace from its enclosing namespace set.
8847 // This is DR275, which we do not retroactively apply to C++98/03.
8848 if (WasQualifiedName) {
8849 if (CurContext->Encloses(OrigContext))
8852 if (CurContext->InEnclosingNamespaceSetOf(OrigContext))
8856 if (NamespaceDecl *NS = dyn_cast<NamespaceDecl>(OrigContext)) {
8857 if (WasQualifiedName)
8859 S.getLangOpts().CPlusPlus11?
8860 diag::err_explicit_instantiation_out_of_scope :
8861 diag::warn_explicit_instantiation_out_of_scope_0x)
8865 S.getLangOpts().CPlusPlus11?
8866 diag::err_explicit_instantiation_unqualified_wrong_namespace :
8867 diag::warn_explicit_instantiation_unqualified_wrong_namespace_0x)
8871 S.getLangOpts().CPlusPlus11?
8872 diag::err_explicit_instantiation_must_be_global :
8873 diag::warn_explicit_instantiation_must_be_global_0x)
8875 S.Diag(D->getLocation(), diag::note_explicit_instantiation_here);
8879 /// Common checks for whether an explicit instantiation of \p D is valid.
8880 static bool CheckExplicitInstantiation(Sema &S, NamedDecl *D,
8881 SourceLocation InstLoc,
8882 bool WasQualifiedName,
8883 TemplateSpecializationKind TSK) {
8884 // C++ [temp.explicit]p13:
8885 // An explicit instantiation declaration shall not name a specialization of
8886 // a template with internal linkage.
8887 if (TSK == TSK_ExplicitInstantiationDeclaration &&
8888 D->getFormalLinkage() == InternalLinkage) {
8889 S.Diag(InstLoc, diag::err_explicit_instantiation_internal_linkage) << D;
8893 // C++11 [temp.explicit]p3: [DR 275]
8894 // An explicit instantiation shall appear in an enclosing namespace of its
8896 if (CheckExplicitInstantiationScope(S, D, InstLoc, WasQualifiedName))
8902 /// Determine whether the given scope specifier has a template-id in it.
8903 static bool ScopeSpecifierHasTemplateId(const CXXScopeSpec &SS) {
8907 // C++11 [temp.explicit]p3:
8908 // If the explicit instantiation is for a member function, a member class
8909 // or a static data member of a class template specialization, the name of
8910 // the class template specialization in the qualified-id for the member
8911 // name shall be a simple-template-id.
8913 // C++98 has the same restriction, just worded differently.
8914 for (NestedNameSpecifier *NNS = SS.getScopeRep(); NNS;
8915 NNS = NNS->getPrefix())
8916 if (const Type *T = NNS->getAsType())
8917 if (isa<TemplateSpecializationType>(T))
8923 /// Make a dllexport or dllimport attr on a class template specialization take
8925 static void dllExportImportClassTemplateSpecialization(
8926 Sema &S, ClassTemplateSpecializationDecl *Def) {
8927 auto *A = cast_or_null<InheritableAttr>(getDLLAttr(Def));
8928 assert(A && "dllExportImportClassTemplateSpecialization called "
8929 "on Def without dllexport or dllimport");
8931 // We reject explicit instantiations in class scope, so there should
8932 // never be any delayed exported classes to worry about.
8933 assert(S.DelayedDllExportClasses.empty() &&
8934 "delayed exports present at explicit instantiation");
8935 S.checkClassLevelDLLAttribute(Def);
8937 // Propagate attribute to base class templates.
8938 for (auto &B : Def->bases()) {
8939 if (auto *BT = dyn_cast_or_null<ClassTemplateSpecializationDecl>(
8940 B.getType()->getAsCXXRecordDecl()))
8941 S.propagateDLLAttrToBaseClassTemplate(Def, A, BT, B.getBeginLoc());
8944 S.referenceDLLExportedClassMethods();
8947 // Explicit instantiation of a class template specialization
8948 DeclResult Sema::ActOnExplicitInstantiation(
8949 Scope *S, SourceLocation ExternLoc, SourceLocation TemplateLoc,
8950 unsigned TagSpec, SourceLocation KWLoc, const CXXScopeSpec &SS,
8951 TemplateTy TemplateD, SourceLocation TemplateNameLoc,
8952 SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgsIn,
8953 SourceLocation RAngleLoc, const ParsedAttributesView &Attr) {
8954 // Find the class template we're specializing
8955 TemplateName Name = TemplateD.get();
8956 TemplateDecl *TD = Name.getAsTemplateDecl();
8957 // Check that the specialization uses the same tag kind as the
8958 // original template.
8959 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
8960 assert(Kind != TTK_Enum &&
8961 "Invalid enum tag in class template explicit instantiation!");
8963 ClassTemplateDecl *ClassTemplate = dyn_cast<ClassTemplateDecl>(TD);
8965 if (!ClassTemplate) {
8966 NonTagKind NTK = getNonTagTypeDeclKind(TD, Kind);
8967 Diag(TemplateNameLoc, diag::err_tag_reference_non_tag) << TD << NTK << Kind;
8968 Diag(TD->getLocation(), diag::note_previous_use);
8972 if (!isAcceptableTagRedeclaration(ClassTemplate->getTemplatedDecl(),
8973 Kind, /*isDefinition*/false, KWLoc,
8974 ClassTemplate->getIdentifier())) {
8975 Diag(KWLoc, diag::err_use_with_wrong_tag)
8977 << FixItHint::CreateReplacement(KWLoc,
8978 ClassTemplate->getTemplatedDecl()->getKindName());
8979 Diag(ClassTemplate->getTemplatedDecl()->getLocation(),
8980 diag::note_previous_use);
8981 Kind = ClassTemplate->getTemplatedDecl()->getTagKind();
8984 // C++0x [temp.explicit]p2:
8985 // There are two forms of explicit instantiation: an explicit instantiation
8986 // definition and an explicit instantiation declaration. An explicit
8987 // instantiation declaration begins with the extern keyword. [...]
8988 TemplateSpecializationKind TSK = ExternLoc.isInvalid()
8989 ? TSK_ExplicitInstantiationDefinition
8990 : TSK_ExplicitInstantiationDeclaration;
8992 if (TSK == TSK_ExplicitInstantiationDeclaration &&
8993 !Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
8994 // Check for dllexport class template instantiation declarations,
8995 // except for MinGW mode.
8996 for (const ParsedAttr &AL : Attr) {
8997 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
8999 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9000 Diag(AL.getLoc(), diag::note_attribute);
9005 if (auto *A = ClassTemplate->getTemplatedDecl()->getAttr<DLLExportAttr>()) {
9007 diag::warn_attribute_dllexport_explicit_instantiation_decl);
9008 Diag(A->getLocation(), diag::note_attribute);
9012 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9013 // instantiation declarations for most purposes.
9014 bool DLLImportExplicitInstantiationDef = false;
9015 if (TSK == TSK_ExplicitInstantiationDefinition &&
9016 Context.getTargetInfo().getCXXABI().isMicrosoft()) {
9017 // Check for dllimport class template instantiation definitions.
9019 ClassTemplate->getTemplatedDecl()->getAttr<DLLImportAttr>();
9020 for (const ParsedAttr &AL : Attr) {
9021 if (AL.getKind() == ParsedAttr::AT_DLLImport)
9023 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9024 // dllexport trumps dllimport here.
9030 TSK = TSK_ExplicitInstantiationDeclaration;
9031 DLLImportExplicitInstantiationDef = true;
9035 // Translate the parser's template argument list in our AST format.
9036 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9037 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9039 // Check that the template argument list is well-formed for this
9041 SmallVector<TemplateArgument, 4> Converted;
9042 if (CheckTemplateArgumentList(ClassTemplate, TemplateNameLoc,
9043 TemplateArgs, false, Converted))
9046 // Find the class template specialization declaration that
9047 // corresponds to these arguments.
9048 void *InsertPos = nullptr;
9049 ClassTemplateSpecializationDecl *PrevDecl
9050 = ClassTemplate->findSpecialization(Converted, InsertPos);
9052 TemplateSpecializationKind PrevDecl_TSK
9053 = PrevDecl ? PrevDecl->getTemplateSpecializationKind() : TSK_Undeclared;
9055 if (TSK == TSK_ExplicitInstantiationDefinition && PrevDecl != nullptr &&
9056 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment()) {
9057 // Check for dllexport class template instantiation definitions in MinGW
9058 // mode, if a previous declaration of the instantiation was seen.
9059 for (const ParsedAttr &AL : Attr) {
9060 if (AL.getKind() == ParsedAttr::AT_DLLExport) {
9062 diag::warn_attribute_dllexport_explicit_instantiation_def);
9068 if (CheckExplicitInstantiation(*this, ClassTemplate, TemplateNameLoc,
9072 ClassTemplateSpecializationDecl *Specialization = nullptr;
9074 bool HasNoEffect = false;
9076 if (CheckSpecializationInstantiationRedecl(TemplateNameLoc, TSK,
9077 PrevDecl, PrevDecl_TSK,
9078 PrevDecl->getPointOfInstantiation(),
9082 // Even though HasNoEffect == true means that this explicit instantiation
9083 // has no effect on semantics, we go on to put its syntax in the AST.
9085 if (PrevDecl_TSK == TSK_ImplicitInstantiation ||
9086 PrevDecl_TSK == TSK_Undeclared) {
9087 // Since the only prior class template specialization with these
9088 // arguments was referenced but not declared, reuse that
9089 // declaration node as our own, updating the source location
9090 // for the template name to reflect our new declaration.
9091 // (Other source locations will be updated later.)
9092 Specialization = PrevDecl;
9093 Specialization->setLocation(TemplateNameLoc);
9097 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9098 DLLImportExplicitInstantiationDef) {
9099 // The new specialization might add a dllimport attribute.
9100 HasNoEffect = false;
9104 if (!Specialization) {
9105 // Create a new class template specialization declaration node for
9106 // this explicit specialization.
9108 = ClassTemplateSpecializationDecl::Create(Context, Kind,
9109 ClassTemplate->getDeclContext(),
9110 KWLoc, TemplateNameLoc,
9114 SetNestedNameSpecifier(*this, Specialization, SS);
9116 if (!HasNoEffect && !PrevDecl) {
9117 // Insert the new specialization.
9118 ClassTemplate->AddSpecialization(Specialization, InsertPos);
9122 // Build the fully-sugared type for this explicit instantiation as
9123 // the user wrote in the explicit instantiation itself. This means
9124 // that we'll pretty-print the type retrieved from the
9125 // specialization's declaration the way that the user actually wrote
9126 // the explicit instantiation, rather than formatting the name based
9127 // on the "canonical" representation used to store the template
9128 // arguments in the specialization.
9129 TypeSourceInfo *WrittenTy
9130 = Context.getTemplateSpecializationTypeInfo(Name, TemplateNameLoc,
9132 Context.getTypeDeclType(Specialization));
9133 Specialization->setTypeAsWritten(WrittenTy);
9135 // Set source locations for keywords.
9136 Specialization->setExternLoc(ExternLoc);
9137 Specialization->setTemplateKeywordLoc(TemplateLoc);
9138 Specialization->setBraceRange(SourceRange());
9140 bool PreviouslyDLLExported = Specialization->hasAttr<DLLExportAttr>();
9141 ProcessDeclAttributeList(S, Specialization, Attr);
9143 // Add the explicit instantiation into its lexical context. However,
9144 // since explicit instantiations are never found by name lookup, we
9145 // just put it into the declaration context directly.
9146 Specialization->setLexicalDeclContext(CurContext);
9147 CurContext->addDecl(Specialization);
9149 // Syntax is now OK, so return if it has no other effect on semantics.
9151 // Set the template specialization kind.
9152 Specialization->setTemplateSpecializationKind(TSK);
9153 return Specialization;
9156 // C++ [temp.explicit]p3:
9157 // A definition of a class template or class member template
9158 // shall be in scope at the point of the explicit instantiation of
9159 // the class template or class member template.
9161 // This check comes when we actually try to perform the
9163 ClassTemplateSpecializationDecl *Def
9164 = cast_or_null<ClassTemplateSpecializationDecl>(
9165 Specialization->getDefinition());
9167 InstantiateClassTemplateSpecialization(TemplateNameLoc, Specialization, TSK);
9168 else if (TSK == TSK_ExplicitInstantiationDefinition) {
9169 MarkVTableUsed(TemplateNameLoc, Specialization, true);
9170 Specialization->setPointOfInstantiation(Def->getPointOfInstantiation());
9173 // Instantiate the members of this class template specialization.
9174 Def = cast_or_null<ClassTemplateSpecializationDecl>(
9175 Specialization->getDefinition());
9177 TemplateSpecializationKind Old_TSK = Def->getTemplateSpecializationKind();
9178 // Fix a TSK_ExplicitInstantiationDeclaration followed by a
9179 // TSK_ExplicitInstantiationDefinition
9180 if (Old_TSK == TSK_ExplicitInstantiationDeclaration &&
9181 (TSK == TSK_ExplicitInstantiationDefinition ||
9182 DLLImportExplicitInstantiationDef)) {
9183 // FIXME: Need to notify the ASTMutationListener that we did this.
9184 Def->setTemplateSpecializationKind(TSK);
9186 if (!getDLLAttr(Def) && getDLLAttr(Specialization) &&
9187 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9188 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9189 // In the MS ABI, an explicit instantiation definition can add a dll
9190 // attribute to a template with a previous instantiation declaration.
9191 // MinGW doesn't allow this.
9192 auto *A = cast<InheritableAttr>(
9193 getDLLAttr(Specialization)->clone(getASTContext()));
9194 A->setInherited(true);
9196 dllExportImportClassTemplateSpecialization(*this, Def);
9200 // Fix a TSK_ImplicitInstantiation followed by a
9201 // TSK_ExplicitInstantiationDefinition
9202 bool NewlyDLLExported =
9203 !PreviouslyDLLExported && Specialization->hasAttr<DLLExportAttr>();
9204 if (Old_TSK == TSK_ImplicitInstantiation && NewlyDLLExported &&
9205 (Context.getTargetInfo().getCXXABI().isMicrosoft() ||
9206 Context.getTargetInfo().getTriple().isWindowsItaniumEnvironment())) {
9207 // In the MS ABI, an explicit instantiation definition can add a dll
9208 // attribute to a template with a previous implicit instantiation.
9209 // MinGW doesn't allow this. We limit clang to only adding dllexport, to
9210 // avoid potentially strange codegen behavior. For example, if we extend
9211 // this conditional to dllimport, and we have a source file calling a
9212 // method on an implicitly instantiated template class instance and then
9213 // declaring a dllimport explicit instantiation definition for the same
9214 // template class, the codegen for the method call will not respect the
9215 // dllimport, while it will with cl. The Def will already have the DLL
9216 // attribute, since the Def and Specialization will be the same in the
9217 // case of Old_TSK == TSK_ImplicitInstantiation, and we already added the
9218 // attribute to the Specialization; we just need to make it take effect.
9219 assert(Def == Specialization &&
9220 "Def and Specialization should match for implicit instantiation");
9221 dllExportImportClassTemplateSpecialization(*this, Def);
9224 // In MinGW mode, export the template instantiation if the declaration
9225 // was marked dllexport.
9226 if (PrevDecl_TSK == TSK_ExplicitInstantiationDeclaration &&
9227 Context.getTargetInfo().getTriple().isWindowsGNUEnvironment() &&
9228 PrevDecl->hasAttr<DLLExportAttr>()) {
9229 dllExportImportClassTemplateSpecialization(*this, Def);
9232 // Set the template specialization kind. Make sure it is set before
9233 // instantiating the members which will trigger ASTConsumer callbacks.
9234 Specialization->setTemplateSpecializationKind(TSK);
9235 InstantiateClassTemplateSpecializationMembers(TemplateNameLoc, Def, TSK);
9238 // Set the template specialization kind.
9239 Specialization->setTemplateSpecializationKind(TSK);
9242 return Specialization;
9245 // Explicit instantiation of a member class of a class template.
9247 Sema::ActOnExplicitInstantiation(Scope *S, SourceLocation ExternLoc,
9248 SourceLocation TemplateLoc, unsigned TagSpec,
9249 SourceLocation KWLoc, CXXScopeSpec &SS,
9250 IdentifierInfo *Name, SourceLocation NameLoc,
9251 const ParsedAttributesView &Attr) {
9254 bool IsDependent = false;
9255 Decl *TagD = ActOnTag(S, TagSpec, Sema::TUK_Reference,
9256 KWLoc, SS, Name, NameLoc, Attr, AS_none,
9257 /*ModulePrivateLoc=*/SourceLocation(),
9258 MultiTemplateParamsArg(), Owned, IsDependent,
9259 SourceLocation(), false, TypeResult(),
9260 /*IsTypeSpecifier*/false,
9261 /*IsTemplateParamOrArg*/false);
9262 assert(!IsDependent && "explicit instantiation of dependent name not yet handled");
9267 TagDecl *Tag = cast<TagDecl>(TagD);
9268 assert(!Tag->isEnum() && "shouldn't see enumerations here");
9270 if (Tag->isInvalidDecl())
9273 CXXRecordDecl *Record = cast<CXXRecordDecl>(Tag);
9274 CXXRecordDecl *Pattern = Record->getInstantiatedFromMemberClass();
9276 Diag(TemplateLoc, diag::err_explicit_instantiation_nontemplate_type)
9277 << Context.getTypeDeclType(Record);
9278 Diag(Record->getLocation(), diag::note_nontemplate_decl_here);
9282 // C++0x [temp.explicit]p2:
9283 // If the explicit instantiation is for a class or member class, the
9284 // elaborated-type-specifier in the declaration shall include a
9285 // simple-template-id.
9287 // C++98 has the same restriction, just worded differently.
9288 if (!ScopeSpecifierHasTemplateId(SS))
9289 Diag(TemplateLoc, diag::ext_explicit_instantiation_without_qualified_id)
9290 << Record << SS.getRange();
9292 // C++0x [temp.explicit]p2:
9293 // There are two forms of explicit instantiation: an explicit instantiation
9294 // definition and an explicit instantiation declaration. An explicit
9295 // instantiation declaration begins with the extern keyword. [...]
9296 TemplateSpecializationKind TSK
9297 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9298 : TSK_ExplicitInstantiationDeclaration;
9300 CheckExplicitInstantiation(*this, Record, NameLoc, true, TSK);
9302 // Verify that it is okay to explicitly instantiate here.
9303 CXXRecordDecl *PrevDecl
9304 = cast_or_null<CXXRecordDecl>(Record->getPreviousDecl());
9305 if (!PrevDecl && Record->getDefinition())
9308 MemberSpecializationInfo *MSInfo = PrevDecl->getMemberSpecializationInfo();
9309 bool HasNoEffect = false;
9310 assert(MSInfo && "No member specialization information?");
9311 if (CheckSpecializationInstantiationRedecl(TemplateLoc, TSK,
9313 MSInfo->getTemplateSpecializationKind(),
9314 MSInfo->getPointOfInstantiation(),
9321 CXXRecordDecl *RecordDef
9322 = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9324 // C++ [temp.explicit]p3:
9325 // A definition of a member class of a class template shall be in scope
9326 // at the point of an explicit instantiation of the member class.
9328 = cast_or_null<CXXRecordDecl>(Pattern->getDefinition());
9330 Diag(TemplateLoc, diag::err_explicit_instantiation_undefined_member)
9331 << 0 << Record->getDeclName() << Record->getDeclContext();
9332 Diag(Pattern->getLocation(), diag::note_forward_declaration)
9336 if (InstantiateClass(NameLoc, Record, Def,
9337 getTemplateInstantiationArgs(Record),
9341 RecordDef = cast_or_null<CXXRecordDecl>(Record->getDefinition());
9347 // Instantiate all of the members of the class.
9348 InstantiateClassMembers(NameLoc, RecordDef,
9349 getTemplateInstantiationArgs(Record), TSK);
9351 if (TSK == TSK_ExplicitInstantiationDefinition)
9352 MarkVTableUsed(NameLoc, RecordDef, true);
9354 // FIXME: We don't have any representation for explicit instantiations of
9355 // member classes. Such a representation is not needed for compilation, but it
9356 // should be available for clients that want to see all of the declarations in
9361 DeclResult Sema::ActOnExplicitInstantiation(Scope *S,
9362 SourceLocation ExternLoc,
9363 SourceLocation TemplateLoc,
9365 // Explicit instantiations always require a name.
9366 // TODO: check if/when DNInfo should replace Name.
9367 DeclarationNameInfo NameInfo = GetNameForDeclarator(D);
9368 DeclarationName Name = NameInfo.getName();
9370 if (!D.isInvalidType())
9371 Diag(D.getDeclSpec().getBeginLoc(),
9372 diag::err_explicit_instantiation_requires_name)
9373 << D.getDeclSpec().getSourceRange() << D.getSourceRange();
9378 // The scope passed in may not be a decl scope. Zip up the scope tree until
9379 // we find one that is.
9380 while ((S->getFlags() & Scope::DeclScope) == 0 ||
9381 (S->getFlags() & Scope::TemplateParamScope) != 0)
9384 // Determine the type of the declaration.
9385 TypeSourceInfo *T = GetTypeForDeclarator(D, S);
9386 QualType R = T->getType();
9391 // A storage-class-specifier shall not be specified in [...] an explicit
9392 // instantiation (14.7.2) directive.
9393 if (D.getDeclSpec().getStorageClassSpec() == DeclSpec::SCS_typedef) {
9394 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_of_typedef)
9397 } else if (D.getDeclSpec().getStorageClassSpec()
9398 != DeclSpec::SCS_unspecified) {
9399 // Complain about then remove the storage class specifier.
9400 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_storage_class)
9401 << FixItHint::CreateRemoval(D.getDeclSpec().getStorageClassSpecLoc());
9403 D.getMutableDeclSpec().ClearStorageClassSpecs();
9406 // C++0x [temp.explicit]p1:
9407 // [...] An explicit instantiation of a function template shall not use the
9408 // inline or constexpr specifiers.
9409 // Presumably, this also applies to member functions of class templates as
9411 if (D.getDeclSpec().isInlineSpecified())
9412 Diag(D.getDeclSpec().getInlineSpecLoc(),
9413 getLangOpts().CPlusPlus11 ?
9414 diag::err_explicit_instantiation_inline :
9415 diag::warn_explicit_instantiation_inline_0x)
9416 << FixItHint::CreateRemoval(D.getDeclSpec().getInlineSpecLoc());
9417 if (D.getDeclSpec().hasConstexprSpecifier() && R->isFunctionType())
9418 // FIXME: Add a fix-it to remove the 'constexpr' and add a 'const' if one is
9419 // not already specified.
9420 Diag(D.getDeclSpec().getConstexprSpecLoc(),
9421 diag::err_explicit_instantiation_constexpr);
9423 // A deduction guide is not on the list of entities that can be explicitly
9425 if (Name.getNameKind() == DeclarationName::CXXDeductionGuideName) {
9426 Diag(D.getDeclSpec().getBeginLoc(), diag::err_deduction_guide_specialized)
9427 << /*explicit instantiation*/ 0;
9431 // C++0x [temp.explicit]p2:
9432 // There are two forms of explicit instantiation: an explicit instantiation
9433 // definition and an explicit instantiation declaration. An explicit
9434 // instantiation declaration begins with the extern keyword. [...]
9435 TemplateSpecializationKind TSK
9436 = ExternLoc.isInvalid()? TSK_ExplicitInstantiationDefinition
9437 : TSK_ExplicitInstantiationDeclaration;
9439 LookupResult Previous(*this, NameInfo, LookupOrdinaryName);
9440 LookupParsedName(Previous, S, &D.getCXXScopeSpec());
9442 if (!R->isFunctionType()) {
9443 // C++ [temp.explicit]p1:
9444 // A [...] static data member of a class template can be explicitly
9445 // instantiated from the member definition associated with its class
9447 // C++1y [temp.explicit]p1:
9448 // A [...] variable [...] template specialization can be explicitly
9449 // instantiated from its template.
9450 if (Previous.isAmbiguous())
9453 VarDecl *Prev = Previous.getAsSingle<VarDecl>();
9454 VarTemplateDecl *PrevTemplate = Previous.getAsSingle<VarTemplateDecl>();
9456 if (!PrevTemplate) {
9457 if (!Prev || !Prev->isStaticDataMember()) {
9458 // We expect to see a static data member here.
9459 Diag(D.getIdentifierLoc(), diag::err_explicit_instantiation_not_known)
9461 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9463 Diag((*P)->getLocation(), diag::note_explicit_instantiation_here);
9467 if (!Prev->getInstantiatedFromStaticDataMember()) {
9468 // FIXME: Check for explicit specialization?
9469 Diag(D.getIdentifierLoc(),
9470 diag::err_explicit_instantiation_data_member_not_instantiated)
9472 Diag(Prev->getLocation(), diag::note_explicit_instantiation_here);
9473 // FIXME: Can we provide a note showing where this was declared?
9477 // Explicitly instantiate a variable template.
9479 // C++1y [dcl.spec.auto]p6:
9480 // ... A program that uses auto or decltype(auto) in a context not
9481 // explicitly allowed in this section is ill-formed.
9483 // This includes auto-typed variable template instantiations.
9484 if (R->isUndeducedType()) {
9485 Diag(T->getTypeLoc().getBeginLoc(),
9486 diag::err_auto_not_allowed_var_inst);
9490 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId) {
9491 // C++1y [temp.explicit]p3:
9492 // If the explicit instantiation is for a variable, the unqualified-id
9493 // in the declaration shall be a template-id.
9494 Diag(D.getIdentifierLoc(),
9495 diag::err_explicit_instantiation_without_template_id)
9497 Diag(PrevTemplate->getLocation(),
9498 diag::note_explicit_instantiation_here);
9502 // Translate the parser's template argument list into our AST format.
9503 TemplateArgumentListInfo TemplateArgs =
9504 makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9506 DeclResult Res = CheckVarTemplateId(PrevTemplate, TemplateLoc,
9507 D.getIdentifierLoc(), TemplateArgs);
9508 if (Res.isInvalid())
9511 // Ignore access control bits, we don't need them for redeclaration
9513 Prev = cast<VarDecl>(Res.get());
9516 // C++0x [temp.explicit]p2:
9517 // If the explicit instantiation is for a member function, a member class
9518 // or a static data member of a class template specialization, the name of
9519 // the class template specialization in the qualified-id for the member
9520 // name shall be a simple-template-id.
9522 // C++98 has the same restriction, just worded differently.
9524 // This does not apply to variable template specializations, where the
9525 // template-id is in the unqualified-id instead.
9526 if (!ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()) && !PrevTemplate)
9527 Diag(D.getIdentifierLoc(),
9528 diag::ext_explicit_instantiation_without_qualified_id)
9529 << Prev << D.getCXXScopeSpec().getRange();
9531 CheckExplicitInstantiation(*this, Prev, D.getIdentifierLoc(), true, TSK);
9533 // Verify that it is okay to explicitly instantiate here.
9534 TemplateSpecializationKind PrevTSK = Prev->getTemplateSpecializationKind();
9535 SourceLocation POI = Prev->getPointOfInstantiation();
9536 bool HasNoEffect = false;
9537 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK, Prev,
9538 PrevTSK, POI, HasNoEffect))
9542 // Instantiate static data member or variable template.
9543 Prev->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9544 // Merge attributes.
9545 ProcessDeclAttributeList(S, Prev, D.getDeclSpec().getAttributes());
9546 if (TSK == TSK_ExplicitInstantiationDefinition)
9547 InstantiateVariableDefinition(D.getIdentifierLoc(), Prev);
9550 // Check the new variable specialization against the parsed input.
9551 if (PrevTemplate && Prev && !Context.hasSameType(Prev->getType(), R)) {
9552 Diag(T->getTypeLoc().getBeginLoc(),
9553 diag::err_invalid_var_template_spec_type)
9554 << 0 << PrevTemplate << R << Prev->getType();
9555 Diag(PrevTemplate->getLocation(), diag::note_template_declared_here)
9556 << 2 << PrevTemplate->getDeclName();
9560 // FIXME: Create an ExplicitInstantiation node?
9561 return (Decl*) nullptr;
9564 // If the declarator is a template-id, translate the parser's template
9565 // argument list into our AST format.
9566 bool HasExplicitTemplateArgs = false;
9567 TemplateArgumentListInfo TemplateArgs;
9568 if (D.getName().getKind() == UnqualifiedIdKind::IK_TemplateId) {
9569 TemplateArgs = makeTemplateArgumentListInfo(*this, *D.getName().TemplateId);
9570 HasExplicitTemplateArgs = true;
9573 // C++ [temp.explicit]p1:
9574 // A [...] function [...] can be explicitly instantiated from its template.
9575 // A member function [...] of a class template can be explicitly
9576 // instantiated from the member definition associated with its class
9578 UnresolvedSet<8> TemplateMatches;
9579 FunctionDecl *NonTemplateMatch = nullptr;
9580 TemplateSpecCandidateSet FailedCandidates(D.getIdentifierLoc());
9581 for (LookupResult::iterator P = Previous.begin(), PEnd = Previous.end();
9583 NamedDecl *Prev = *P;
9584 if (!HasExplicitTemplateArgs) {
9585 if (CXXMethodDecl *Method = dyn_cast<CXXMethodDecl>(Prev)) {
9586 QualType Adjusted = adjustCCAndNoReturn(R, Method->getType(),
9587 /*AdjustExceptionSpec*/true);
9588 if (Context.hasSameUnqualifiedType(Method->getType(), Adjusted)) {
9589 if (Method->getPrimaryTemplate()) {
9590 TemplateMatches.addDecl(Method, P.getAccess());
9592 // FIXME: Can this assert ever happen? Needs a test.
9593 assert(!NonTemplateMatch && "Multiple NonTemplateMatches");
9594 NonTemplateMatch = Method;
9600 FunctionTemplateDecl *FunTmpl = dyn_cast<FunctionTemplateDecl>(Prev);
9604 TemplateDeductionInfo Info(FailedCandidates.getLocation());
9605 FunctionDecl *Specialization = nullptr;
9606 if (TemplateDeductionResult TDK
9607 = DeduceTemplateArguments(FunTmpl,
9608 (HasExplicitTemplateArgs ? &TemplateArgs
9610 R, Specialization, Info)) {
9611 // Keep track of almost-matches.
9612 FailedCandidates.addCandidate()
9613 .set(P.getPair(), FunTmpl->getTemplatedDecl(),
9614 MakeDeductionFailureInfo(Context, TDK, Info));
9619 // Target attributes are part of the cuda function signature, so
9620 // the cuda target of the instantiated function must match that of its
9621 // template. Given that C++ template deduction does not take
9622 // target attributes into account, we reject candidates here that
9623 // have a different target.
9624 if (LangOpts.CUDA &&
9625 IdentifyCUDATarget(Specialization,
9626 /* IgnoreImplicitHDAttr = */ true) !=
9627 IdentifyCUDATarget(D.getDeclSpec().getAttributes())) {
9628 FailedCandidates.addCandidate().set(
9629 P.getPair(), FunTmpl->getTemplatedDecl(),
9630 MakeDeductionFailureInfo(Context, TDK_CUDATargetMismatch, Info));
9634 TemplateMatches.addDecl(Specialization, P.getAccess());
9637 FunctionDecl *Specialization = NonTemplateMatch;
9638 if (!Specialization) {
9639 // Find the most specialized function template specialization.
9640 UnresolvedSetIterator Result = getMostSpecialized(
9641 TemplateMatches.begin(), TemplateMatches.end(), FailedCandidates,
9642 D.getIdentifierLoc(),
9643 PDiag(diag::err_explicit_instantiation_not_known) << Name,
9644 PDiag(diag::err_explicit_instantiation_ambiguous) << Name,
9645 PDiag(diag::note_explicit_instantiation_candidate));
9647 if (Result == TemplateMatches.end())
9650 // Ignore access control bits, we don't need them for redeclaration checking.
9651 Specialization = cast<FunctionDecl>(*Result);
9654 // C++11 [except.spec]p4
9655 // In an explicit instantiation an exception-specification may be specified,
9656 // but is not required.
9657 // If an exception-specification is specified in an explicit instantiation
9658 // directive, it shall be compatible with the exception-specifications of
9659 // other declarations of that function.
9660 if (auto *FPT = R->getAs<FunctionProtoType>())
9661 if (FPT->hasExceptionSpec()) {
9663 diag::err_mismatched_exception_spec_explicit_instantiation;
9664 if (getLangOpts().MicrosoftExt)
9665 DiagID = diag::ext_mismatched_exception_spec_explicit_instantiation;
9666 bool Result = CheckEquivalentExceptionSpec(
9667 PDiag(DiagID) << Specialization->getType(),
9668 PDiag(diag::note_explicit_instantiation_here),
9669 Specialization->getType()->getAs<FunctionProtoType>(),
9670 Specialization->getLocation(), FPT, D.getBeginLoc());
9671 // In Microsoft mode, mismatching exception specifications just cause a
9673 if (!getLangOpts().MicrosoftExt && Result)
9677 if (Specialization->getTemplateSpecializationKind() == TSK_Undeclared) {
9678 Diag(D.getIdentifierLoc(),
9679 diag::err_explicit_instantiation_member_function_not_instantiated)
9681 << (Specialization->getTemplateSpecializationKind() ==
9682 TSK_ExplicitSpecialization);
9683 Diag(Specialization->getLocation(), diag::note_explicit_instantiation_here);
9687 FunctionDecl *PrevDecl = Specialization->getPreviousDecl();
9688 if (!PrevDecl && Specialization->isThisDeclarationADefinition())
9689 PrevDecl = Specialization;
9692 bool HasNoEffect = false;
9693 if (CheckSpecializationInstantiationRedecl(D.getIdentifierLoc(), TSK,
9695 PrevDecl->getTemplateSpecializationKind(),
9696 PrevDecl->getPointOfInstantiation(),
9700 // FIXME: We may still want to build some representation of this
9701 // explicit specialization.
9703 return (Decl*) nullptr;
9706 // HACK: libc++ has a bug where it attempts to explicitly instantiate the
9708 // valarray<size_t>::valarray(size_t) and
9709 // valarray<size_t>::~valarray()
9710 // that it declared to have internal linkage with the internal_linkage
9711 // attribute. Ignore the explicit instantiation declaration in this case.
9712 if (Specialization->hasAttr<InternalLinkageAttr>() &&
9713 TSK == TSK_ExplicitInstantiationDeclaration) {
9714 if (auto *RD = dyn_cast<CXXRecordDecl>(Specialization->getDeclContext()))
9715 if (RD->getIdentifier() && RD->getIdentifier()->isStr("valarray") &&
9716 RD->isInStdNamespace())
9717 return (Decl*) nullptr;
9720 ProcessDeclAttributeList(S, Specialization, D.getDeclSpec().getAttributes());
9722 // In MSVC mode, dllimported explicit instantiation definitions are treated as
9723 // instantiation declarations.
9724 if (TSK == TSK_ExplicitInstantiationDefinition &&
9725 Specialization->hasAttr<DLLImportAttr>() &&
9726 Context.getTargetInfo().getCXXABI().isMicrosoft())
9727 TSK = TSK_ExplicitInstantiationDeclaration;
9729 Specialization->setTemplateSpecializationKind(TSK, D.getIdentifierLoc());
9731 if (Specialization->isDefined()) {
9732 // Let the ASTConsumer know that this function has been explicitly
9733 // instantiated now, and its linkage might have changed.
9734 Consumer.HandleTopLevelDecl(DeclGroupRef(Specialization));
9735 } else if (TSK == TSK_ExplicitInstantiationDefinition)
9736 InstantiateFunctionDefinition(D.getIdentifierLoc(), Specialization);
9738 // C++0x [temp.explicit]p2:
9739 // If the explicit instantiation is for a member function, a member class
9740 // or a static data member of a class template specialization, the name of
9741 // the class template specialization in the qualified-id for the member
9742 // name shall be a simple-template-id.
9744 // C++98 has the same restriction, just worded differently.
9745 FunctionTemplateDecl *FunTmpl = Specialization->getPrimaryTemplate();
9746 if (D.getName().getKind() != UnqualifiedIdKind::IK_TemplateId && !FunTmpl &&
9747 D.getCXXScopeSpec().isSet() &&
9748 !ScopeSpecifierHasTemplateId(D.getCXXScopeSpec()))
9749 Diag(D.getIdentifierLoc(),
9750 diag::ext_explicit_instantiation_without_qualified_id)
9751 << Specialization << D.getCXXScopeSpec().getRange();
9753 CheckExplicitInstantiation(
9755 FunTmpl ? (NamedDecl *)FunTmpl
9756 : Specialization->getInstantiatedFromMemberFunction(),
9757 D.getIdentifierLoc(), D.getCXXScopeSpec().isSet(), TSK);
9759 // FIXME: Create some kind of ExplicitInstantiationDecl here.
9760 return (Decl*) nullptr;
9764 Sema::ActOnDependentTag(Scope *S, unsigned TagSpec, TagUseKind TUK,
9765 const CXXScopeSpec &SS, IdentifierInfo *Name,
9766 SourceLocation TagLoc, SourceLocation NameLoc) {
9767 // This has to hold, because SS is expected to be defined.
9768 assert(Name && "Expected a name in a dependent tag");
9770 NestedNameSpecifier *NNS = SS.getScopeRep();
9774 TagTypeKind Kind = TypeWithKeyword::getTagTypeKindForTypeSpec(TagSpec);
9776 if (TUK == TUK_Declaration || TUK == TUK_Definition) {
9777 Diag(NameLoc, diag::err_dependent_tag_decl)
9778 << (TUK == TUK_Definition) << Kind << SS.getRange();
9782 // Create the resulting type.
9783 ElaboratedTypeKeyword Kwd = TypeWithKeyword::getKeywordForTagTypeKind(Kind);
9784 QualType Result = Context.getDependentNameType(Kwd, NNS, Name);
9786 // Create type-source location information for this type.
9788 DependentNameTypeLoc TL = TLB.push<DependentNameTypeLoc>(Result);
9789 TL.setElaboratedKeywordLoc(TagLoc);
9790 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9791 TL.setNameLoc(NameLoc);
9792 return CreateParsedType(Result, TLB.getTypeSourceInfo(Context, Result));
9796 Sema::ActOnTypenameType(Scope *S, SourceLocation TypenameLoc,
9797 const CXXScopeSpec &SS, const IdentifierInfo &II,
9798 SourceLocation IdLoc) {
9802 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9804 getLangOpts().CPlusPlus11 ?
9805 diag::warn_cxx98_compat_typename_outside_of_template :
9806 diag::ext_typename_outside_of_template)
9807 << FixItHint::CreateRemoval(TypenameLoc);
9809 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
9810 QualType T = CheckTypenameType(TypenameLoc.isValid()? ETK_Typename : ETK_None,
9811 TypenameLoc, QualifierLoc, II, IdLoc);
9815 TypeSourceInfo *TSI = Context.CreateTypeSourceInfo(T);
9816 if (isa<DependentNameType>(T)) {
9817 DependentNameTypeLoc TL = TSI->getTypeLoc().castAs<DependentNameTypeLoc>();
9818 TL.setElaboratedKeywordLoc(TypenameLoc);
9819 TL.setQualifierLoc(QualifierLoc);
9820 TL.setNameLoc(IdLoc);
9822 ElaboratedTypeLoc TL = TSI->getTypeLoc().castAs<ElaboratedTypeLoc>();
9823 TL.setElaboratedKeywordLoc(TypenameLoc);
9824 TL.setQualifierLoc(QualifierLoc);
9825 TL.getNamedTypeLoc().castAs<TypeSpecTypeLoc>().setNameLoc(IdLoc);
9828 return CreateParsedType(T, TSI);
9832 Sema::ActOnTypenameType(Scope *S,
9833 SourceLocation TypenameLoc,
9834 const CXXScopeSpec &SS,
9835 SourceLocation TemplateKWLoc,
9836 TemplateTy TemplateIn,
9837 IdentifierInfo *TemplateII,
9838 SourceLocation TemplateIILoc,
9839 SourceLocation LAngleLoc,
9840 ASTTemplateArgsPtr TemplateArgsIn,
9841 SourceLocation RAngleLoc) {
9842 if (TypenameLoc.isValid() && S && !S->getTemplateParamParent())
9844 getLangOpts().CPlusPlus11 ?
9845 diag::warn_cxx98_compat_typename_outside_of_template :
9846 diag::ext_typename_outside_of_template)
9847 << FixItHint::CreateRemoval(TypenameLoc);
9849 // Strangely, non-type results are not ignored by this lookup, so the
9850 // program is ill-formed if it finds an injected-class-name.
9851 if (TypenameLoc.isValid()) {
9853 dyn_cast_or_null<CXXRecordDecl>(computeDeclContext(SS, false));
9854 if (LookupRD && LookupRD->getIdentifier() == TemplateII) {
9856 diag::ext_out_of_line_qualified_id_type_names_constructor)
9857 << TemplateII << 0 /*injected-class-name used as template name*/
9858 << (TemplateKWLoc.isValid() ? 1 : 0 /*'template'/'typename' keyword*/);
9862 // Translate the parser's template argument list in our AST format.
9863 TemplateArgumentListInfo TemplateArgs(LAngleLoc, RAngleLoc);
9864 translateTemplateArguments(TemplateArgsIn, TemplateArgs);
9866 TemplateName Template = TemplateIn.get();
9867 if (DependentTemplateName *DTN = Template.getAsDependentTemplateName()) {
9868 // Construct a dependent template specialization type.
9869 assert(DTN && "dependent template has non-dependent name?");
9870 assert(DTN->getQualifier() == SS.getScopeRep());
9871 QualType T = Context.getDependentTemplateSpecializationType(ETK_Typename,
9872 DTN->getQualifier(),
9873 DTN->getIdentifier(),
9876 // Create source-location information for this type.
9877 TypeLocBuilder Builder;
9878 DependentTemplateSpecializationTypeLoc SpecTL
9879 = Builder.push<DependentTemplateSpecializationTypeLoc>(T);
9880 SpecTL.setElaboratedKeywordLoc(TypenameLoc);
9881 SpecTL.setQualifierLoc(SS.getWithLocInContext(Context));
9882 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9883 SpecTL.setTemplateNameLoc(TemplateIILoc);
9884 SpecTL.setLAngleLoc(LAngleLoc);
9885 SpecTL.setRAngleLoc(RAngleLoc);
9886 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9887 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9888 return CreateParsedType(T, Builder.getTypeSourceInfo(Context, T));
9891 QualType T = CheckTemplateIdType(Template, TemplateIILoc, TemplateArgs);
9895 // Provide source-location information for the template specialization type.
9896 TypeLocBuilder Builder;
9897 TemplateSpecializationTypeLoc SpecTL
9898 = Builder.push<TemplateSpecializationTypeLoc>(T);
9899 SpecTL.setTemplateKeywordLoc(TemplateKWLoc);
9900 SpecTL.setTemplateNameLoc(TemplateIILoc);
9901 SpecTL.setLAngleLoc(LAngleLoc);
9902 SpecTL.setRAngleLoc(RAngleLoc);
9903 for (unsigned I = 0, N = TemplateArgs.size(); I != N; ++I)
9904 SpecTL.setArgLocInfo(I, TemplateArgs[I].getLocInfo());
9906 T = Context.getElaboratedType(ETK_Typename, SS.getScopeRep(), T);
9907 ElaboratedTypeLoc TL = Builder.push<ElaboratedTypeLoc>(T);
9908 TL.setElaboratedKeywordLoc(TypenameLoc);
9909 TL.setQualifierLoc(SS.getWithLocInContext(Context));
9911 TypeSourceInfo *TSI = Builder.getTypeSourceInfo(Context, T);
9912 return CreateParsedType(T, TSI);
9916 /// Determine whether this failed name lookup should be treated as being
9917 /// disabled by a usage of std::enable_if.
9918 static bool isEnableIf(NestedNameSpecifierLoc NNS, const IdentifierInfo &II,
9919 SourceRange &CondRange, Expr *&Cond) {
9920 // We must be looking for a ::type...
9921 if (!II.isStr("type"))
9924 // ... within an explicitly-written template specialization...
9925 if (!NNS || !NNS.getNestedNameSpecifier()->getAsType())
9927 TypeLoc EnableIfTy = NNS.getTypeLoc();
9928 TemplateSpecializationTypeLoc EnableIfTSTLoc =
9929 EnableIfTy.getAs<TemplateSpecializationTypeLoc>();
9930 if (!EnableIfTSTLoc || EnableIfTSTLoc.getNumArgs() == 0)
9932 const TemplateSpecializationType *EnableIfTST = EnableIfTSTLoc.getTypePtr();
9934 // ... which names a complete class template declaration...
9935 const TemplateDecl *EnableIfDecl =
9936 EnableIfTST->getTemplateName().getAsTemplateDecl();
9937 if (!EnableIfDecl || EnableIfTST->isIncompleteType())
9940 // ... called "enable_if".
9941 const IdentifierInfo *EnableIfII =
9942 EnableIfDecl->getDeclName().getAsIdentifierInfo();
9943 if (!EnableIfII || !EnableIfII->isStr("enable_if"))
9946 // Assume the first template argument is the condition.
9947 CondRange = EnableIfTSTLoc.getArgLoc(0).getSourceRange();
9949 // Dig out the condition.
9951 if (EnableIfTSTLoc.getArgLoc(0).getArgument().getKind()
9952 != TemplateArgument::Expression)
9955 Cond = EnableIfTSTLoc.getArgLoc(0).getSourceExpression();
9957 // Ignore Boolean literals; they add no value.
9958 if (isa<CXXBoolLiteralExpr>(Cond->IgnoreParenCasts()))
9964 /// Build the type that describes a C++ typename specifier,
9965 /// e.g., "typename T::type".
9967 Sema::CheckTypenameType(ElaboratedTypeKeyword Keyword,
9968 SourceLocation KeywordLoc,
9969 NestedNameSpecifierLoc QualifierLoc,
9970 const IdentifierInfo &II,
9971 SourceLocation IILoc) {
9973 SS.Adopt(QualifierLoc);
9975 DeclContext *Ctx = computeDeclContext(SS);
9977 // If the nested-name-specifier is dependent and couldn't be
9978 // resolved to a type, build a typename type.
9979 assert(QualifierLoc.getNestedNameSpecifier()->isDependent());
9980 return Context.getDependentNameType(Keyword,
9981 QualifierLoc.getNestedNameSpecifier(),
9985 // If the nested-name-specifier refers to the current instantiation,
9986 // the "typename" keyword itself is superfluous. In C++03, the
9987 // program is actually ill-formed. However, DR 382 (in C++0x CD1)
9988 // allows such extraneous "typename" keywords, and we retroactively
9989 // apply this DR to C++03 code with only a warning. In any case we continue.
9991 if (RequireCompleteDeclContext(SS, Ctx))
9994 DeclarationName Name(&II);
9995 LookupResult Result(*this, Name, IILoc, LookupOrdinaryName);
9996 LookupQualifiedName(Result, Ctx, SS);
9997 unsigned DiagID = 0;
9998 Decl *Referenced = nullptr;
9999 switch (Result.getResultKind()) {
10000 case LookupResult::NotFound: {
10001 // If we're looking up 'type' within a template named 'enable_if', produce
10002 // a more specific diagnostic.
10003 SourceRange CondRange;
10004 Expr *Cond = nullptr;
10005 if (isEnableIf(QualifierLoc, II, CondRange, Cond)) {
10006 // If we have a condition, narrow it down to the specific failed
10010 std::string FailedDescription;
10011 std::tie(FailedCond, FailedDescription) =
10012 findFailedBooleanCondition(Cond);
10014 Diag(FailedCond->getExprLoc(),
10015 diag::err_typename_nested_not_found_requirement)
10016 << FailedDescription
10017 << FailedCond->getSourceRange();
10021 Diag(CondRange.getBegin(), diag::err_typename_nested_not_found_enable_if)
10022 << Ctx << CondRange;
10026 DiagID = diag::err_typename_nested_not_found;
10030 case LookupResult::FoundUnresolvedValue: {
10031 // We found a using declaration that is a value. Most likely, the using
10032 // declaration itself is meant to have the 'typename' keyword.
10033 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10035 Diag(IILoc, diag::err_typename_refers_to_using_value_decl)
10036 << Name << Ctx << FullRange;
10037 if (UnresolvedUsingValueDecl *Using
10038 = dyn_cast<UnresolvedUsingValueDecl>(Result.getRepresentativeDecl())){
10039 SourceLocation Loc = Using->getQualifierLoc().getBeginLoc();
10040 Diag(Loc, diag::note_using_value_decl_missing_typename)
10041 << FixItHint::CreateInsertion(Loc, "typename ");
10044 // Fall through to create a dependent typename type, from which we can recover
10048 case LookupResult::NotFoundInCurrentInstantiation:
10049 // Okay, it's a member of an unknown instantiation.
10050 return Context.getDependentNameType(Keyword,
10051 QualifierLoc.getNestedNameSpecifier(),
10054 case LookupResult::Found:
10055 if (TypeDecl *Type = dyn_cast<TypeDecl>(Result.getFoundDecl())) {
10056 // C++ [class.qual]p2:
10057 // In a lookup in which function names are not ignored and the
10058 // nested-name-specifier nominates a class C, if the name specified
10059 // after the nested-name-specifier, when looked up in C, is the
10060 // injected-class-name of C [...] then the name is instead considered
10061 // to name the constructor of class C.
10063 // Unlike in an elaborated-type-specifier, function names are not ignored
10064 // in typename-specifier lookup. However, they are ignored in all the
10065 // contexts where we form a typename type with no keyword (that is, in
10066 // mem-initializer-ids, base-specifiers, and elaborated-type-specifiers).
10068 // FIXME: That's not strictly true: mem-initializer-id lookup does not
10069 // ignore functions, but that appears to be an oversight.
10070 auto *LookupRD = dyn_cast_or_null<CXXRecordDecl>(Ctx);
10071 auto *FoundRD = dyn_cast<CXXRecordDecl>(Type);
10072 if (Keyword == ETK_Typename && LookupRD && FoundRD &&
10073 FoundRD->isInjectedClassName() &&
10074 declaresSameEntity(LookupRD, cast<Decl>(FoundRD->getParent())))
10075 Diag(IILoc, diag::ext_out_of_line_qualified_id_type_names_constructor)
10076 << &II << 1 << 0 /*'typename' keyword used*/;
10078 // We found a type. Build an ElaboratedType, since the
10079 // typename-specifier was just sugar.
10080 MarkAnyDeclReferenced(Type->getLocation(), Type, /*OdrUse=*/false);
10081 return Context.getElaboratedType(Keyword,
10082 QualifierLoc.getNestedNameSpecifier(),
10083 Context.getTypeDeclType(Type));
10086 // C++ [dcl.type.simple]p2:
10087 // A type-specifier of the form
10088 // typename[opt] nested-name-specifier[opt] template-name
10089 // is a placeholder for a deduced class type [...].
10090 if (getLangOpts().CPlusPlus17) {
10091 if (auto *TD = getAsTypeTemplateDecl(Result.getFoundDecl())) {
10092 return Context.getElaboratedType(
10093 Keyword, QualifierLoc.getNestedNameSpecifier(),
10094 Context.getDeducedTemplateSpecializationType(TemplateName(TD),
10095 QualType(), false));
10099 DiagID = diag::err_typename_nested_not_type;
10100 Referenced = Result.getFoundDecl();
10103 case LookupResult::FoundOverloaded:
10104 DiagID = diag::err_typename_nested_not_type;
10105 Referenced = *Result.begin();
10108 case LookupResult::Ambiguous:
10112 // If we get here, it's because name lookup did not find a
10113 // type. Emit an appropriate diagnostic and return an error.
10114 SourceRange FullRange(KeywordLoc.isValid() ? KeywordLoc : SS.getBeginLoc(),
10116 Diag(IILoc, DiagID) << FullRange << Name << Ctx;
10118 Diag(Referenced->getLocation(), diag::note_typename_refers_here)
10124 // See Sema::RebuildTypeInCurrentInstantiation
10125 class CurrentInstantiationRebuilder
10126 : public TreeTransform<CurrentInstantiationRebuilder> {
10127 SourceLocation Loc;
10128 DeclarationName Entity;
10131 typedef TreeTransform<CurrentInstantiationRebuilder> inherited;
10133 CurrentInstantiationRebuilder(Sema &SemaRef,
10134 SourceLocation Loc,
10135 DeclarationName Entity)
10136 : TreeTransform<CurrentInstantiationRebuilder>(SemaRef),
10137 Loc(Loc), Entity(Entity) { }
10139 /// Determine whether the given type \p T has already been
10142 /// For the purposes of type reconstruction, a type has already been
10143 /// transformed if it is NULL or if it is not dependent.
10144 bool AlreadyTransformed(QualType T) {
10145 return T.isNull() || !T->isDependentType();
10148 /// Returns the location of the entity whose type is being
10150 SourceLocation getBaseLocation() { return Loc; }
10152 /// Returns the name of the entity whose type is being rebuilt.
10153 DeclarationName getBaseEntity() { return Entity; }
10155 /// Sets the "base" location and entity when that
10156 /// information is known based on another transformation.
10157 void setBase(SourceLocation Loc, DeclarationName Entity) {
10159 this->Entity = Entity;
10162 ExprResult TransformLambdaExpr(LambdaExpr *E) {
10163 // Lambdas never need to be transformed.
10167 } // end anonymous namespace
10169 /// Rebuilds a type within the context of the current instantiation.
10171 /// The type \p T is part of the type of an out-of-line member definition of
10172 /// a class template (or class template partial specialization) that was parsed
10173 /// and constructed before we entered the scope of the class template (or
10174 /// partial specialization thereof). This routine will rebuild that type now
10175 /// that we have entered the declarator's scope, which may produce different
10176 /// canonical types, e.g.,
10179 /// template<typename T>
10181 /// typedef T* pointer;
10182 /// pointer data();
10185 /// template<typename T>
10186 /// typename X<T>::pointer X<T>::data() { ... }
10189 /// Here, the type "typename X<T>::pointer" will be created as a DependentNameType,
10190 /// since we do not know that we can look into X<T> when we parsed the type.
10191 /// This function will rebuild the type, performing the lookup of "pointer"
10192 /// in X<T> and returning an ElaboratedType whose canonical type is the same
10193 /// as the canonical type of T*, allowing the return types of the out-of-line
10194 /// definition and the declaration to match.
10195 TypeSourceInfo *Sema::RebuildTypeInCurrentInstantiation(TypeSourceInfo *T,
10196 SourceLocation Loc,
10197 DeclarationName Name) {
10198 if (!T || !T->getType()->isDependentType())
10201 CurrentInstantiationRebuilder Rebuilder(*this, Loc, Name);
10202 return Rebuilder.TransformType(T);
10205 ExprResult Sema::RebuildExprInCurrentInstantiation(Expr *E) {
10206 CurrentInstantiationRebuilder Rebuilder(*this, E->getExprLoc(),
10207 DeclarationName());
10208 return Rebuilder.TransformExpr(E);
10211 bool Sema::RebuildNestedNameSpecifierInCurrentInstantiation(CXXScopeSpec &SS) {
10212 if (SS.isInvalid())
10215 NestedNameSpecifierLoc QualifierLoc = SS.getWithLocInContext(Context);
10216 CurrentInstantiationRebuilder Rebuilder(*this, SS.getRange().getBegin(),
10217 DeclarationName());
10218 NestedNameSpecifierLoc Rebuilt
10219 = Rebuilder.TransformNestedNameSpecifierLoc(QualifierLoc);
10227 /// Rebuild the template parameters now that we know we're in a current
10229 bool Sema::RebuildTemplateParamsInCurrentInstantiation(
10230 TemplateParameterList *Params) {
10231 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10232 Decl *Param = Params->getParam(I);
10234 // There is nothing to rebuild in a type parameter.
10235 if (isa<TemplateTypeParmDecl>(Param))
10238 // Rebuild the template parameter list of a template template parameter.
10239 if (TemplateTemplateParmDecl *TTP
10240 = dyn_cast<TemplateTemplateParmDecl>(Param)) {
10241 if (RebuildTemplateParamsInCurrentInstantiation(
10242 TTP->getTemplateParameters()))
10248 // Rebuild the type of a non-type template parameter.
10249 NonTypeTemplateParmDecl *NTTP = cast<NonTypeTemplateParmDecl>(Param);
10250 TypeSourceInfo *NewTSI
10251 = RebuildTypeInCurrentInstantiation(NTTP->getTypeSourceInfo(),
10252 NTTP->getLocation(),
10253 NTTP->getDeclName());
10257 if (NewTSI->getType()->isUndeducedType()) {
10258 // C++17 [temp.dep.expr]p3:
10259 // An id-expression is type-dependent if it contains
10260 // - an identifier associated by name lookup with a non-type
10261 // template-parameter declared with a type that contains a
10262 // placeholder type (7.1.7.4),
10263 NewTSI = SubstAutoTypeSourceInfo(NewTSI, Context.DependentTy);
10266 if (NewTSI != NTTP->getTypeSourceInfo()) {
10267 NTTP->setTypeSourceInfo(NewTSI);
10268 NTTP->setType(NewTSI->getType());
10275 /// Produces a formatted string that describes the binding of
10276 /// template parameters to template arguments.
10278 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10279 const TemplateArgumentList &Args) {
10280 return getTemplateArgumentBindingsText(Params, Args.data(), Args.size());
10284 Sema::getTemplateArgumentBindingsText(const TemplateParameterList *Params,
10285 const TemplateArgument *Args,
10286 unsigned NumArgs) {
10287 SmallString<128> Str;
10288 llvm::raw_svector_ostream Out(Str);
10290 if (!Params || Params->size() == 0 || NumArgs == 0)
10291 return std::string();
10293 for (unsigned I = 0, N = Params->size(); I != N; ++I) {
10302 if (const IdentifierInfo *Id = Params->getParam(I)->getIdentifier()) {
10303 Out << Id->getName();
10309 Args[I].print(getPrintingPolicy(), Out);
10316 void Sema::MarkAsLateParsedTemplate(FunctionDecl *FD, Decl *FnD,
10317 CachedTokens &Toks) {
10321 auto LPT = std::make_unique<LateParsedTemplate>();
10323 // Take tokens to avoid allocations
10324 LPT->Toks.swap(Toks);
10326 LateParsedTemplateMap.insert(std::make_pair(FD, std::move(LPT)));
10328 FD->setLateTemplateParsed(true);
10331 void Sema::UnmarkAsLateParsedTemplate(FunctionDecl *FD) {
10334 FD->setLateTemplateParsed(false);
10337 bool Sema::IsInsideALocalClassWithinATemplateFunction() {
10338 DeclContext *DC = CurContext;
10341 if (CXXRecordDecl *RD = dyn_cast<CXXRecordDecl>(CurContext)) {
10342 const FunctionDecl *FD = RD->isLocalClass();
10343 return (FD && FD->getTemplatedKind() != FunctionDecl::TK_NonTemplate);
10344 } else if (DC->isTranslationUnit() || DC->isNamespace())
10347 DC = DC->getParent();
10353 /// Walk the path from which a declaration was instantiated, and check
10354 /// that every explicit specialization along that path is visible. This enforces
10355 /// C++ [temp.expl.spec]/6:
10357 /// If a template, a member template or a member of a class template is
10358 /// explicitly specialized then that specialization shall be declared before
10359 /// the first use of that specialization that would cause an implicit
10360 /// instantiation to take place, in every translation unit in which such a
10361 /// use occurs; no diagnostic is required.
10363 /// and also C++ [temp.class.spec]/1:
10365 /// A partial specialization shall be declared before the first use of a
10366 /// class template specialization that would make use of the partial
10367 /// specialization as the result of an implicit or explicit instantiation
10368 /// in every translation unit in which such a use occurs; no diagnostic is
10370 class ExplicitSpecializationVisibilityChecker {
10372 SourceLocation Loc;
10373 llvm::SmallVector<Module *, 8> Modules;
10376 ExplicitSpecializationVisibilityChecker(Sema &S, SourceLocation Loc)
10377 : S(S), Loc(Loc) {}
10379 void check(NamedDecl *ND) {
10380 if (auto *FD = dyn_cast<FunctionDecl>(ND))
10381 return checkImpl(FD);
10382 if (auto *RD = dyn_cast<CXXRecordDecl>(ND))
10383 return checkImpl(RD);
10384 if (auto *VD = dyn_cast<VarDecl>(ND))
10385 return checkImpl(VD);
10386 if (auto *ED = dyn_cast<EnumDecl>(ND))
10387 return checkImpl(ED);
10391 void diagnose(NamedDecl *D, bool IsPartialSpec) {
10392 auto Kind = IsPartialSpec ? Sema::MissingImportKind::PartialSpecialization
10393 : Sema::MissingImportKind::ExplicitSpecialization;
10394 const bool Recover = true;
10396 // If we got a custom set of modules (because only a subset of the
10397 // declarations are interesting), use them, otherwise let
10398 // diagnoseMissingImport intelligently pick some.
10399 if (Modules.empty())
10400 S.diagnoseMissingImport(Loc, D, Kind, Recover);
10402 S.diagnoseMissingImport(Loc, D, D->getLocation(), Modules, Kind, Recover);
10405 // Check a specific declaration. There are three problematic cases:
10407 // 1) The declaration is an explicit specialization of a template
10409 // 2) The declaration is an explicit specialization of a member of an
10410 // templated class.
10411 // 3) The declaration is an instantiation of a template, and that template
10412 // is an explicit specialization of a member of a templated class.
10414 // We don't need to go any deeper than that, as the instantiation of the
10415 // surrounding class / etc is not triggered by whatever triggered this
10416 // instantiation, and thus should be checked elsewhere.
10417 template<typename SpecDecl>
10418 void checkImpl(SpecDecl *Spec) {
10419 bool IsHiddenExplicitSpecialization = false;
10420 if (Spec->getTemplateSpecializationKind() == TSK_ExplicitSpecialization) {
10421 IsHiddenExplicitSpecialization =
10422 Spec->getMemberSpecializationInfo()
10423 ? !S.hasVisibleMemberSpecialization(Spec, &Modules)
10424 : !S.hasVisibleExplicitSpecialization(Spec, &Modules);
10426 checkInstantiated(Spec);
10429 if (IsHiddenExplicitSpecialization)
10430 diagnose(Spec->getMostRecentDecl(), false);
10433 void checkInstantiated(FunctionDecl *FD) {
10434 if (auto *TD = FD->getPrimaryTemplate())
10438 void checkInstantiated(CXXRecordDecl *RD) {
10439 auto *SD = dyn_cast<ClassTemplateSpecializationDecl>(RD);
10443 auto From = SD->getSpecializedTemplateOrPartial();
10444 if (auto *TD = From.dyn_cast<ClassTemplateDecl *>())
10446 else if (auto *TD =
10447 From.dyn_cast<ClassTemplatePartialSpecializationDecl *>()) {
10448 if (!S.hasVisibleDeclaration(TD))
10449 diagnose(TD, true);
10454 void checkInstantiated(VarDecl *RD) {
10455 auto *SD = dyn_cast<VarTemplateSpecializationDecl>(RD);
10459 auto From = SD->getSpecializedTemplateOrPartial();
10460 if (auto *TD = From.dyn_cast<VarTemplateDecl *>())
10462 else if (auto *TD =
10463 From.dyn_cast<VarTemplatePartialSpecializationDecl *>()) {
10464 if (!S.hasVisibleDeclaration(TD))
10465 diagnose(TD, true);
10470 void checkInstantiated(EnumDecl *FD) {}
10472 template<typename TemplDecl>
10473 void checkTemplate(TemplDecl *TD) {
10474 if (TD->isMemberSpecialization()) {
10475 if (!S.hasVisibleMemberSpecialization(TD, &Modules))
10476 diagnose(TD->getMostRecentDecl(), false);
10480 } // end anonymous namespace
10482 void Sema::checkSpecializationVisibility(SourceLocation Loc, NamedDecl *Spec) {
10483 if (!getLangOpts().Modules)
10486 ExplicitSpecializationVisibilityChecker(*this, Loc).check(Spec);
10489 /// Check whether a template partial specialization that we've discovered
10490 /// is hidden, and produce suitable diagnostics if so.
10491 void Sema::checkPartialSpecializationVisibility(SourceLocation Loc,
10493 llvm::SmallVector<Module *, 8> Modules;
10494 if (!hasVisibleDeclaration(Spec, &Modules))
10495 diagnoseMissingImport(Loc, Spec, Spec->getLocation(), Modules,
10496 MissingImportKind::PartialSpecialization,